Culinary/catering/restaurant workers, what was your happiest experience with a diner?

When someone recognizes how hard you've been working, running around, etc (I was a hostess/busser) it means a lot. The management never gave much recognition, but there was a nice lady who stopped me and told me they've been watching how hard I've been busting my ass and slipped me a 20$ tip. Best feeling in the world.