I'd give my best, but I damn well remembered those who didn't appreciate my efforts and stiffed me. I won't tell you the rest of the story....
Believe it or not, lots of service folks will give as good as they get.
Chew on that for a while before you decide to f**k with some kids head.
I believe every young person should be forced to work either as a food server or at a convenience store as part of their work experience. If one were constantly on the other end of being treated similar to a vending machine, they'd be more sympathetic and sensitive to those that do service work and would be more understanding and fair with them. Nobody deserves to be treated like dirt although a few bring it upon themselves.