Why am I attracted to this jerk?

There is this guy who is the BIGGEST jerkiest most conceded guy I've ever met and I absolutely can't stand him. He makes EVERYTHING a competition and he ALWAYS has to win. Hes so errogant and annoying and brags about EVERYTHING he does.....BUT I've been thinking about him for 2 weeks now, and I can't get the kid out of my head. His jerkiness secretly turns me on, and I don't really know why. I'm always thinking about him, looking for him, when he even bumps into me, it drives me insane. Why? And What should I do?