We stopped at McDonald's for breakfast. There was a car next to us in the other drive-thru lane with a couple boys in the back seat and since my window was down from ordering I waved like an idiot to them--just to make them smile while we were waiting in line.

We get up to the window to pay and the mother had already taken care of our order.

I know this isn't the grandest story of humanity, and that many others have experienced one or both sides of the interaction, but it was the first time it's ever happened for me and I really appreciated the gesture. I'm going to reciprocate next time I have the chance.