616. We will always, always, always find a problem.

(Ever wonder why when one problem resolves, another one takes its place? It's not that the world is against you—but your brain might be, in a sense. Researchers asked volunteers to pick out threatening-looking people from computer-generated faces. "As we showed people fewer and fewer threatening faces over time, we found that they expanded their definition of 'threatening' to include a wider range of faces," writes researcher David Levari, PhD. "In other words, when they ran out of threatening faces to find, they started calling faces threatening that they used to call harmless.")

617. The eyes are the mirrors of our souls, as they say, so there’s probably no surprise that simply looking into each others’ eyes can make us fall for each other, even if we don’t know jack about each other. It has been proven that when someone is gazing at you, the person’s body produces a chemical called phenylethylamine, which is associated with the fight-or-flightresponse. So if you decide to continue looking at each other, you’re asking for Cupid’s arrow.

618. That flutter of butterflies in your tummy is actually your stomach crying for help, because all the blood is rushing to the muscles and stomach isn’t getting enough supply.

619. A marvelous 75-year long study, which was conducted by a group of Harvard researchers, has shown that love is really all that matters. The participants’ lifelong experiences revealed that happiness and life fulfillment revolved around love or simply searching for love.

620. All people are born with basic emotions, and normal reactions to these emotions are not necessarily learned from watching their parents. We know this, because even children who are born blind will still have the same facial expressions as everybody else, like smiling when they’re happy, or frowning when they’re sad.