I've been going to a couple games every year since 2005. My experience is that the old fans lack enthusiasm. They have a lot of pride and many still live in the golden years.
The younger fans, although enthusiastic lack a lot of football knowledge. Whether its screaming while we're on offense or chanting for David Carr they dont know the intricacies of the game. One thing I know is that many of them focus only on the ball and who's holding it... they fail to understand that there are 21 other men on the field affecting the play.
My best fan experience was probably Wembley... The fans were fun to be around, they understood basic football and if they had any questions there was somebody (whether it was me, or another football fanatic) to explain it to them. It had the atmosphere of a big game.
Going to Oakland was by far the worst... I'm not gonna explain much because there isnt much to talk about, all I gotta say is that there were times I wanted to kick some punks ass and there were times I feared for my life. And it was a pre-season game