Well I am one of them for sure :)
Just wanted to write about this lingering thought.
Usually a tennis fan is happy when his "guy" is doing great out there on the court and disappointed when he is losing.
But being a Federer fan is different -- even if he isn't doing great at the moment
1) You know never know when he will move on to a different gear and dig himself out so no sweat there... you are riveted till the end.
2) Even if he loses you realise that Federer himself has not Fallen apart, his expressions, his post match talk usually say that he is happy that he reached to this point(usually semifinals or finals)
3) Finally I think a Federer fan is happy to just see him play
win or lose we all know --- you are God of tennis himself--