I had a friend in my ward in Oklahoma a few years ago who was a very casual Texas fan, but HATED BYU. I don't think he knew any players on UT, but his eyes would light up when BYU came up, and he would go off about how much he hates BYU.
I talked to him a few days before the BYU-UT game in Provo that year. He said he bought plane tickets, game tickets, and a hotel room. He was so excited. He bought a bunch of UT gear. He spent a lot of money to go to that game. He kept talking about how great it would be for UT to humiliate BYU in Provo.
Then Taysom makes UT his yewt and BYU pummels them in record-breaking fashion, and gets their coaching staff fired.
He couldn't even look me in the eye after that. Amazing.