It's not about the money though is it? It's about giving someone who works silly hours at minimum wage with no pension or perks something to brighten up their day in the hope that they provide a better service to the next people they serve.
I worked as a waiter for a couple of months whilst waiting for my qualifications to be converted and it was the most miserable, depressing, degrading job I've ever had to do. Sucking up to people all day long is horrendous but now and then a tip from a customer showing their appreciation would cheer me up a bit, and that's why I tip.
I can't think of a single person who chooses to be a waiter / barman / cab driver / whatever. They're there because it's often all they can do / get.
So do you tip the staff at tesco, or primark or any other minimum wage retail outlet where tey have to suck up to people all day and do the most miserable depressing and degrading job ever?
or how about mcdonalds that's surely gotta be worse than restaurant work?
. I'm great with faces but crap with names.