March 23rd, 2005, was the worst day of my entire life.

Most people my age probably have other worst days that stick out for them. I'm sure September 11th, 2001 is a pretty strong contender. I was 14 when I watched the twin towers of the World Trade Center collapse on the small, fuzzy, wall-mounted television alongside my classmates in third period Algebra, permanently changing life in America in ways that seemed scary and foreign to children like me who had grown up in the comparatively carefree decade of the 90s. August 29th, 2005 is another good choice, when Hurricane Katrina slammed into the southeastern coastal states and devastated New Orleans. There's Columbine in '99, Virginia Tech in '07, and a whole host of other atrocities and natural disasters throughout that period to choose from.

But for me, like many of my peers, all of those events were tragic in a distant, sad kind of way that made you stop and appreciate how lucky you were to have been sheltered from them—to not know someone who was crushed to death by the smoking rubble of the collapsing towers or who drowned in the rushing, black murk of the hurricane floodwaters as the levees failed. I'm grateful I never had to live through a school shooting and know what it's like to see kids I grew up with bleeding out in the halls of my high school, or worse still, to be one of them, gasping out your final breaths with a ragged hole in your chest as your mind stubbornly fixates on the ridiculous idea that you never told that cute girl in your English class that you liked her, and now, you'll never get to.

However sad those events might have been, they were all things that happened to other people for me. Numbers on a screen.

It's funny how you can think of yourself as a cold, rational utilitarian until something slams into you from out of nowhere and affects you, personally. If you had asked me on March 22nd whether the greater tragedy was a tsunami killing hundreds of thousands of people or a car accident killing two, I would have blinked at you and told you that your question was ridiculous. How could you ever measure just two lives against hundreds of thousands?

If you'd asked me on March 23rd, my answer would have changed. You can measure two lives against millions when they're lives that are important to you. It turns out that subjective perspective matters quite a lot when evaluating the relative magnitude of tragedy.

I remember that day with uncanny clarity. It was a Wednesday. It was cloudy and cold. I had turned 18 two months before and was riding out the end of my Senior year with a healthy dose of senioritis. My mother insisted on cooking for me even though I was already late and likely to miss my bus, but she guilted me into sitting with her by reminding me that she only got to have so many more breakfasts with her little boy. Dad had gone to work before I came downstairs, taking Brianna with him to drop her off at kindergarten, and I sat in the kitchen fidgeting and staring dramatically at my digital watch while mom cooked eggs and poured orange juice. After we ate, she dropped me off at school and tried to kiss me goodbye, but I wasn't having any of it. I muttered a quick "see ya" and slipped out the passenger side door, hoping that none of my peers had spotted the Senior getting out of his mother's car.

You might think it's a little strange that my parents had one kid leaving for college at the same time that they had another one in kindergarten—why have just twenty years of responsibility for another human when you can double your fun, right? It's not that they were bad planners or so crazy about parenting that they wanted to continue forever. They'd originally planned on having exactly one child, so after I was born my father got a vasectomy. Both of my parents had been only children and perfectly happy with the experience, and for 13 years I was too. There were no annoying fights with siblings, no need to share any of my toys, and I got more Christmas presents than any of my friends with a larger family did.

When my mom got pregnant with Brianna in the summer of '99, everybody was shocked, and my father most of all. As the doctor explained to them later, there are very rare cases where the vas deferens (which is the tube severed during the procedure) will regrow on its own, and if it does, the sperm can escape from their surgically-imposed captivity to seek the sweet, sweet freedom they were destined for. Brianna had originated as one of those tiny, jail-breaking sperm cells, and on February 14th, in the year 2000, my parents suddenly had a brand new baby girl to start raising all over again less than five years before their own sweet, childless freedom should have begun. My dad called Bri his "oopsie baby" until she was three years old and joked that she was the most painful Valentine's Day gift he'd ever given mom, who didn't seem especially amused about any of it.

Still, they both loved Brianna to death. Mom was secretly thrilled that she could now have the girl she'd always wanted, and dad had a new pupil to put through his curriculum of epic nerdery just as his prior one—yours truly—was starting to go through his "I'm too cool for my parents" phase. The timing couldn't have been better, as far as I was concerned. They were suddenly way too busy with the baby to pay much attention to me, and I had all the time I wanted to work on my EverQuest raid gear sets, hang out at the local hobby shop, and master the finer points of beating Diablo II on the "Hell" difficulty setting, which was what absorbed the majority of my time that summer.

Fast forward to 2005, and things had been going really well for the family as we'd settled into our new rhythm of a four-person household. My relationship with Brianna had gone through the stages of "baby I ignore" and "toddler I ignore and sometimes watch for mom" to finally arrive at "cute small child I tolerate watching while I play videogames." In five short years she'd managed to usurp me as the new family favorite, with both of our parents wrapped around her sticky little fingers, and she used her powers of persuasion to force me to hang out with her as often as possible. While I pretended that her constant admiration annoyed me, secretly I was flattered that this adorable little girl seemed to like me so much. She wanted to do everything her older brother did, go everywhere he went, and more often than not my mom just smiled and told me to let her.

I didn't know quite what to make of her back then. My friends were all close in age to their siblings, with very different interactions than Bri and I had, and I sometimes felt like I was more of a goofy uncle to her than an older brother. I loved her, I played with her, but I also kept a small distance between us, since I knew that I'd be going away to college that fall, and I didn't want either of us to be too sad about it when it happened. She'd grown a little less interested in me as she started making new friends in her kindergarten class anyway, and by her fifth birthday party, as I watched her squealing happily alongside a dozen other children in rainbow-colored party hats, I was confident that I'd be able to slip away in September with a minimal amount of sobbing (from either of us).

Just five weeks after that birthday party, as I gave my mom my hasty final farewell and strolled into my high school on that cold March bitch of a day, I remember thinking about how I'd probably miss Bri even more than I'd miss my parents. Looking back years later, the utter irony of that sentiment was in no way lost on me.

School that day was remarkable only in how unremarkable it was. I floated through my classes with the dismissive indifference common to second-semester Seniors whose grades were bulletproof and whose college acceptance had already been locked in. My letter from Caltech's Computer Science program had come in January, just days after my own birthday, and I was psyched that I'd be spending the next four years in the sunny climate of Pasadena, California. MIT had been my first choice, but apparently I didn't quite make their cut. Whatever. Cambridge would have been full of stuffy East Coast types anyway, and who knew if I could have afforded the tuition there even if I'd gotten in? My dad was a software engineer and my mom was a homemaker. We were comfortable but not loaded, especially now that they had my sister to think about, and Caltech was offering me a full ride. I'd crushed my SATs and ACTs and wasn't too shabby on the track team, either.

As someone who grew up solidly in the age of the internet with a tech-savvy, forward-thinking father, I had big dreams of making an impact in the still-fledgling technology industry of the Web 2.0, and even rarer, the opportunity to make those dreams come true. Microsoft, Apple, and Dell were the computer companies everyone talked about back then, the monolithic behemoths who had successfully weathered the dot-com crash of 2001, but Dad was pushing me to keep my eyes on some of the smaller, more interesting firms that had also survived and seemed to be on the cutting edge of modern software development. Google was just beginning to wake up and stretch its many-tentacled reach, Facebook was a kooky novelty product still in its infancy, and Amazon was only known as a bookseller back then.

I didn't know where I wanted to work, exactly, but I knew what kind of work I wanted to do—my friends and I had been obsessed with books like Snow Crash and Otherland, and we spent a good chunk of our free time playing massively multiplayer online games where you could take on the guise of a fantasy character and explore a vast, virtual world alongside other people from all over the globe. I wanted to be a part of taking that technology to the next level. Haptic bodysuits, neural jacks, whatever actually turned out to be feasible. I wasn't picky about what I got to work on. I just wanted to make it happen and then hang out with my friends in cyberspace, preferably while wielding laser swords.

Some people see a movie like The Matrix and go, "What an awful dystopian future." I see a movie like The Matrix and go, "The robots can have my body. Just sign me up for downloadable karate moves, please."

My final school period finished at 3:45pm, and by 4:00pm on the worst day of my life I was outside waiting for the bus as usual. I spent the long ride home arguing with three of my geekiest friends about what we should all play together that night. Track practice was Tuesdays and Thursdays, and I was supposed to leave Friday morning to go to an out-of-town all-weekend meet. Wednesday was going to be my only solid gaming night for what felt like an eternity, and I was adamant that I wanted to use it playing World of Wacraft, my latest online obsession, no matter how hard my best friend Mark pushed for City of Heroes or Kyle whined that we never played D&D anymore. By the time we arrived at my stop, my cajoling had worn them down and they'd agreed to join me on my quest to eradicate Lordaeron's entire murloc population. I ran all the way home, excited to spend the next eight hours wrapped in a warm cocoon of virtual fantasy violence with my pals.

Our front door was locked when I got there, which was so unusual that I had to take a step back and make sure I had the right house. Brianna's kindergarten let out at 2:30, and my mom always ran her errands in the morning. Sometimes they went to the library together to pick out new books, but they'd always be back by 4:00 at the latest. Usually mom would be getting ready to make dinner and playing with my sister about now. I had my own key, of course, but I couldn't remember the last time I'd had to use it. I dug it out of my pocket and let myself in, ditched my shoes, and dumped my backpack on the floor in the foyer as I advanced cautiously into my house.

"Mom? Dad? Brianna?" I called out.

The house was dead silent. Hollow feeling. No rush of water in the pipes, no muted hum of televisions or computers, no dinner smells or laughter from the kitchen. I remember shivering and feeling vaguely uneasy even before I noticed the blinking light on our answering machine with five unheard messages. In order, they were from the police, the hospital, the police, Bri's kindergarten teacher, and the police.

I sank to the floor as I listened to each of them play, immediately fearing the worst and having those fears confirmed with each successive message. Words assailed me and spun through my head, each short phrase landing like a fresh punch to the gut.

"...accident on Miller's Road..."

"...in critical condition..."

"...two fatalities confirmed..."

"...no one came to get Bri today..."

"...waiting for you down at St. Mary's..."

I didn't have a car, so instead I called Mark's parents and managed to stammer a request for help through panicked tears. Mrs. Johnson drove over immediately with Mark, both of them ashen-faced at the news, and we went together to pick up Bri and go to the hospital. We didn't arrive in time to say goodbye.

Later, as I sat with my head in my hands in a hospital waiting room and Mrs. Johnson tended to Brianna, a police officer gave me the details of what had happened. Mom was running her usual errands that morning when she'd decided to meet dad for a surprise lunch. They took dad's car, had a nice meal together, and were headed back along Miller's Road when a distracted driver coming from the other direction accidentally veered out of his lane to hit them head-on at 60mph.

I'd taken a full year of physics, so I understood exactly what that meant. With a head-on collision between two cars both traveling at that speed, deceleration from 60mph to 0mph occurs in about 200 milliseconds. It's not exactly like slamming into a brick wall, because the cars will have different masses and won't be perfectly aligned, but neither is it unlike slamming into a brick wall. Most cars are designed so that the front of the vehicle deforms in a controlled manner during a crash like this, absorbing as much of the energy into the frame as possible while the airbags inflate with a burst of nitrogen. As the passenger bodies collide with the airbags, the nitrogen is pushed out through small holes in the back of the bag which further dissipates energy. At lower speeds, this is often enough to save lives. At higher speeds, well... there's only so much engineering we can do to fight physics. Don't text and drive, people.

Dad and the other driver were both killed on impact. Mom went to the hospital in critical condition and died three and half hours later, right around the same time I was walking into my silent, empty house.

Bri and I stayed with the Johnsons that night. I was barely responsive, basically in shock, and Brianna wouldn't stop asking me when mom and dad were going to come and take us home. She hadn't been allowed to see the bodies, and I didn't know how to tell her what had happened.

Instead of going to my track meet or playing videogames, I spent all weekend in a dazed fog of talking to life insurance agents and wading through paperwork with a huge dose of assistance from Mark's dad, while Mrs. Johnson took care of Bri. They really helped us a lot in those early weeks, and I'll always be grateful to them for that. I don't know how I would have managed things without their support.

My parents didn't have a massive amount of savings, but between that and the life insurance payout, there was enough to pay off the mortgage and provide Brianna and me with a few years of living expenses. It soon became clear that nothing about my immediate plans had to change. I had my golden ticket to Caltech. Four years of room and board, tuition, and supplies would all be paid for. My high school would have excused my absence for the rest of the year and still granted me a diploma. I could move on with exactly the life my parents had wanted for me, and that I had wanted for myself.

The only question was what to do with my sister. My grandparents had all passed away when I was Bri's age, and as only children, my parents had left us with no aunts, uncles, or cousins that could have taken custody. Bringing her along with me to Pasadena was out of the question—full time attendance in a Computer Science program at one of the top schools in the nation doesn't leave much time for child care. If I had asked, I have no doubt that the Johnsons would have adopted her. But as close as I was with Mark, they were strangers to Brianna.

At first I told myself that I could just leave for four years, graduate, and then come back and get her, but the more I thought about it, the more it became obvious that it wouldn't work out. After graduation there would be internships to attend, a career to build, and the long working hours that young programmers are famously expected to keep to prove their dedication to their craft at the cutting edge firms that hire them. Then there would be girlfriends, travel opportunities, and a life of my own I'd be building, without Brianna, whether I'd intended to or not.

Even if I did come back after all that, even if we did our best to keep in touch, I knew that the cheerful little sticky-fingered shadow who tried to follow me everywhere would have become a stranger to me. And then what? Would I throw it all away and put the brakes on the career I'd worked so hard for to live with her in our small hometown as she finished high school? Would I take her back with me to wherever I ended up, forcing her to leave behind the friends she'd made and her new family to live in a big, unfamiliar city with a distant brother who worked all the time? Neither option made sense.

The price of following my dreams would have been sacrificing any chance of a real relationship with my sister, and robbing that little girl of the only shred of her previous life that was left to her.

We'd already lost two of our family members. I wasn't prepared for both of us to have to lose the only remaining one, too. Bri was all I had, and I was all she had, now. What was I supposed to do?

I signed formal papers of guardianship a month later, and that was that. I was effectively an eighteen year-old single father with a high-school diploma and a five year-old girl to take care of. Instead of learning how to program, I learned how to braid hair. Instead of cutting-edge software, I made sandwiches with the edges cut off. I did it all for Bri, and even today I wouldn't change a damn thing about my decision.

Anyway, fuck March 23rd.