Just the other day. We grabbed Quiznos for dinner. A man in a Navy uniform came in after us. My oldest son walked up to him and shook his hand and thanked him for his service. We paid for his food before we were noticed. I try to do these kinds of things often to show my children that there is still some kindness in the world.
When I actually took my own time to do something else, but instead done some of my brother's school work on computer due to him being sick and guess what.... even if I wanted to hear a THANK YOU he would not of said it anyways, but again I was at least nice enough to do it, but failed a freaking test by a land slide LOL :)
Never thought about it, just raised that way. Five minutes ago, my girl is asleep and was curled into a ball, I pulled up the covers on her, knowing she was cold. I'll never feel the need to mention it and don't expect any reward. I guess it makes me feel better and that's my reward. I suppose I do unselfish things for selfish reasons.
Benmin, I'm not sure this question came out the way you intended. It's obvious from the answers already given that most people are "nice" to strangers without expecting anything in return.
I suppose that, in my case, I want them to be nice right back at me, so that's a bit selfish. Mostly they are but when they're not I just shrug it off. The world doesn't need grumps, grouches, and -- wait for it -- curmudgeons.