Rant: Why does my wife think Sunday football is optional?

I swear this happens EVERY weekend. I block off 1pm-4pm for the games - ONE timeslot - and somehow that's when she decides we NEED to go to Costco, or visit her parents, or 'just quickly' run errands. Meanwhile she gets her book club every Thursday night and that's sacred. I'm not even asking for much here? Just one afternoon where I can watch my team without being asked where I put the grocery list every 5 minutes. Am I being unreasonable or...