One day, I was sitting in a fast food restaurant when I noticed an older gentleman walking in. As he   1   by, I smiled at him, sincerely welcoming his   2  . That was all.

A few minutes later he stopped in front of my   3   because he really wanted to tell me how much he had   4   my smile. “Not many people give a friendly   5   to a stranger these days,” he said, “And I just wanted to thank you for your kind   6  .”