Human beings as a rule will always try to put themselves above everyone else. We validate our existence by witnessing those who are worse off than us, or lowering those who we believe are above us to or below our level.
Example 1: If you see someone who's happier, wealthier, stronger, or better than you in any of the thousands of ways we judge people, you'll first look for or imagine all the ways you're better than them. If that doesn't work, and sometimes even if it does, you'll dislike that person. If misfortune falls on them and they end up worse than you, the dislike stops. Not because of guilt, but because you now feel better about yourself.
Example 2: Charity work. Ask anyone who does it and they'll almost always say they enjoy the feeling they get from helping others. That's because they're attending to those they feel (subliminally at least) are beneath them. Those that are being helped will either accept the aid or reject it because they feel that they don't need it, that they're better than it.
Example 3: FML, and those videos on the internet of people being idiots and hurting themselves. It's pretty self-explanatory. You feel better after reading/watching people you think are either idiots or incredibly unlucky.
It's cruel, and when you look at it from a distance it's unbelievably stupid, but it's just human nature. Most people don't realize it, or don't care, and that's okay. I for one will openly admit that I enjoy messing with people, it's fun and usually funny.
"Pessimist is what an optimist calls a realist."
