I LOVE stuff like that.
Once a few weeks back, I let an older lady (not even "senior," just older... 50s or 60s) cross the street. No one was behind me or on the other side of the street, but she was already halfway across, so I let her pass. She got up to the sidewalk, and she blew me a kiss. I raved about it for the whole day, and I still remember it.
I love love love when stuff like that happens. It stays with you for so long.