It's the second half, the wind has picked up, and you've been sitting on bare metal for over an hour. The cold has gone straight through your jeans. You're wrapped in a blanket, holding a coffee that went cold ages ago, and checking the clock more than the scoreboard.
Then there's your back. Bleachers have nothing to lean on. By the end of a long game, or the third game of a tournament day, you're shifting around trying to get comfortable, and your lower back is letting you know about it.