Kissing, laughing, dreaming — they are some of life's greatest pleasures that at first glance, all seem useless from an evolutionary perspective. But they're not useless! Or so scientists think. And they're pretty sure! See if you can guess the most-accepted reasons for human eccentricities.
Source: Flickr User Wsobchak
Why Do We Do That? See What You Know About Human Nature
What social function does laughter serve?