Something I've been pondering.

To note, when I was a food runner (basically a waiter without tips but only delivered orders, didn't receive them), I would actually bow when I left tables. Wasn't even an overly classy restaurant, but damned if it didn't get the waiters I worked with tons of tips. Even got some myself a couple times (generally unheard of). Of course they'd joke with me about it, but I actually had people asking where I went when I quit. Little courtesies make customer service interactions that much more enjoyable, on both ends.