It's ok to be a fan of the game and not be a fan of one club. The trouble we Americans have is we are so used to our tiny little world that it's overwhelming when we try to comprehend a worldwide game and we aren't the best at it.
Watch some EPL or La Liga games (sorry
@Kafka ) and learn the game. You'll probably find a few teams that catch your eye. It's going to be hard to become a fan of a single team since you won't really have a vested interest in any club.
One thing that I've really fallen in love with is international soccer. The US men are just good enough to get you interested plus you're vested being an American. If you hate America, well you can just piss off then.