[mattvanhorn]

I was listening to Robson Moura (BJJ black belt) talk about why he loves the art so much. He said something like: when you walk out of a karate class, after a lot of sparring, you feel like a tough-guy who's ready to kick some ass, but when you walk out of a BJJ class, where people smaller than you have just repeatedly demonstrated that they could kill you with their bare hands, you feel very humbled.

The effects on ego tend to weed out a lot of assholes, and between this and the mental challenges of the sport, it is one of the reasons I've come to love it. (Ryron & Rener also do a pretty good job of distinguishing between self-defense and sport jiu jitsu, at least in the videos I've seen from them.)