Football game back in 2006, I believe. I happened to be in Tuscon at the time, so I went to the game. I cheered for BYU, but I am not much of a boisterous fan. I don't go crazy every play.
The band came over to our section to blow their horns in our faces. I just laughed at them. I mean, really...what was the point of that?
I was sitting next to an old lady Arizona fan and she was just as bad. Couldn't stop telling me off the whole game as I mostly ignored her.
All the Arizona fans seemed more happy to talk trash than they were happy about their win.
Lots of really disgusting signs about mormons and our morals and their lack of such. Sex dolls all over the place with signs about John Beck needing to use them.

After that, and the one time I went to a BYU-Utah game back in 1992 (a whole other story, but suffice to say, Utah fans really do suck), I have just decided to not go to any opposing teams home games ever again.

Last year, at the game vs ASU at LES, there was an ASU fan who was sitting in our section (not close to the ASU section) who was just being a blowhard and then wondering why nobody felt like being nice to him. I actually said to him, "if you just cheered for your team, I don't think anyone would mind" He finally got the message and left before the 4th quarter.

If you go to a game just to antagonize people, then maybe you should just stay home and rethink your life.

I mean really, if you just walked up to a stranger on the street and got in their face and started yelling at them, you would deserve a fist to your nose, right?