As a kid, I was taught my manners. Of course, not every child absorbs those manners as well as their parents would like. I'd like to think that I was a pretty good sponge, though.

Anyway, my point is, I always make sure to hold open doors. And if someone holds a door open for me, I always say thanks. Sometimes, I don't speak loud enough and I hope that the person holding the door open didn't think I was an ungrateful loser or something like that.