I'm a bit short of gentlemanly experiences, but here's one that might bear recounting, just for the final line.
It was a blazing hot day and I stopped to offer two elderly ladies a lift. One refused, the other saw Mrs Didge in the car and accepted. So they got in. I went out of my way to drop them where they were going (no big deal) and as they got out one of them said, "Thank you very much. I'll do the same for somebody else."
I thought it was a good example of "what goes around, comes around." Nice lady.