game and he said "Go Cougs!" Even in that environment — where I had seen people in BYU gear all evening — my mind was elsewhere and by the time I connected what he had said and mumbled some response we were past each other and it was mildly awkward.
I am a huge BYU fan, so I have nothing against being greeted by strangers who share my fandom. I'm just acknowledging that some of the encounters with fellow fans can take you by surprise. If you see someone's BYU gear and then decide to say something, you have usually had at least a few seconds (and sometimes longer) to process the situation — that's often more than the other person gets before the face to face encounter is over.