It seems to me that the best people in the world are those who give without thought of receiving. The true sense of gratification comes from this and not from some idea that there will be a reward for one's actions. I feel that the world would be a better place if everyone took the hint.
Never the less, I do appreciate this post to some degree. I'm in the habit of telling every person who assists me in any way, even if it's the cashier in a store, "Thank You" and I wish them a wonderful day.