Why do I want to have sex with someone I hate?

Well he is nice to talk to. But he can be arrogant, weird and rude at times. Because of these negative traits, he’s fine as a friend only. He has a nice body but I’ve met men with nice bodies before so that can’t be it. I work with him sometimes and he’s always bothering me, being rude, and talking shit about other people. He’s also kind of racist (we’re the same ethnicity, except he is mixed race so he believes he has free rein to say terrible racial oriented things about others). At first I thought he was attractive, but as time went on he has shown his true colors and now I realize he has such an icky personality. Yet for some reason I fantasize quite often about fucking him. This has never happened to me before.