I think most of us are selfish by nature. Expressing kindness to others with out expectations shows the world what all of us should strive to be like. My "love language"(as my wife puts it) is doing for others. It makes me feel extremely happy when someone goes out of there way to do something for me, whether it be saying something nice or helping me with something I need. Because of this, I try to do the same for others with any opportunity I get. What I find most interesting is the effect it has on the most undeserving. In most cases it seems to show them that kindness and selflessness still exist in a world of greed. I also find that they are most appreciative. Like someone posted earlier, you never no what kind of effect you might have on someone. That one nice gesture might be something that turns someone's day(or life) around.