Why are people so damn rude?

Not only on the internet, but in general. Why do so many people seem to get pleasure from tearing other people down? It doesn't benefit anyone in the long run. Why not lift them up with something positive, or say something funny or witty that doesn't make you sound like a bitter twat?

I find it physically hard not to be compassionate or consider the way that my actions/words will make someone else feel. If I can help someone, I feel that it is literally my duty to do it. We're only alive for around 80 years, why are we trying to make each other's time here miserable instead of just doing little things to make each other happier? Call me a bleeding-heart hippie, but I was just raised that way, I guess; to actually care for my fellow humans and to show respect, even in the face of someone who wants to act like a douche. I feel like a dying breed, in that respect.

Does anyone else see this/feel this way? We need more positive energy up in this bitch!