NFL gaf just operates the way I'd imagine a meetup of different fanbases would. Not so much fighting but just talking shit and poking fun of the others. Nothing wrong with that. Sports breed competition and shit talking is part of that.
NBA-gaf was pretty much the same way. I think the only major difference was just being unwelcoming to new members. If your new and criticize someone they're always someone with a weird "who the hell are you"
But we never posted pictures of our poop. Never.