It's one thing, holding open the door for someone at a grocery store, or the library, or just about anyplace else. But the doughnut shop is a different thing altogether. This is a get-in-and-out-as-fast-as-you-can operation. There's no room for courtesy or chivalry here.
I've always favored kids as a player. If I walked out of the locker room and there were 100 people there and 50 of them were kids, I'd sign the 50 kids before anything else.