Hmm, I think part of the problem is I tend to like assholes.
As both kleinbl00 and insomniasexx mentioned, "assholes" are fun. I think they lack certain inhibitions that are vicariously entertaining to a point. They can make fun friends but shitty partners. It's funny though, nobody thinks that they are assholes.
I would beg to differ. I'm kind of tertiary friends with a large crowd of assholes that know they are assholes and in fact in a way seem to capitalize on it. I would argue this makes them perhaps bigger assholes than the norm because they are purposefully indulging in the natural tendencies they have. They are like "We are assholes! So let us be the ultimate asshole!" It can be fun to be an asshole, too, in certain ways. It's fun to say "I don't give a fuck what anyone thinks of me, I'm just going to be offensive." But I don't like to take it to the step where anyone actually gets hurt.
I guess my point is that nobody ever thinks they are the villain. In life, we are all the heroes in the play and tend to rationalize our less than stellar behaviors. Therefore, if you know you are an asshole, it's likely that you don't realize the full impact of your assholishness. If you are hanging out with people that are assholes and know that by being assholes are hurting others, that's not being an asshole, that's being evil.
I like people who don't give a shit or at least appear not to. I think the thing is that I appreciate people who don't care too much about what other people think; people who have irreverent senses of humor who are willing to push the envelope and don't mind breaking the rules. (Fence climbing, sign toppling, etc). So as result I find myself drawn to funny assholes as they exhibit these qualities.