What makes a fan?

Another miserable week in Philadelphia sports. The Phillies are out and the Eagles are down, but that is not the post today.

I had coffee with a collegue today. I know that he is a Yankees fan and that he grew up in New York. So reasonably I asked if he was Giants or Jets, and he said neither. Ok, what then? He said I don't follow professional football. Ok I can understand that. (Correction I don't understand it but can accepted that it occurs). He then goes on the explain why, he moved around too much in his professional career and couldn't get attached to a team. If he had to choose he would go back to his days in Los Angeles and choose the USC Trojans, after all their players are paid and therefore professional. A lame joke.

It got me thinking, shouldn't the same reasoning ring true with his choice of the Yankees as well. He clearly likes football but somehow reject the team he supported as a kid because they haven't won anything for a while. He should have just said I prefer college football or something. I just don't understand.