Once I was having lunch with a friend in a nice restaurant in Las Vegas and our waiter was awful. I mean exceptionally bad.
My friend called him over and said, 'You do know why you will not be receiving a tip, don't you?' Next thing I know a new waitperson and better service The new waitperson got a great tip, too. I must say I was embarrassed as all get out, but it worked.
I tip anywhere from 15% on up.
Oh, the absolute worse service I have ever received was in an upscale restaurant - Morton's in Chicago. It was a Thursday night, I had just closed my first big patent deal and was celebrating. Foolish waiter, the man in the expensive suit left him chump change, I was dressed in a nice dress and ready to blow out all the stops. Instead, we finished our meal and blew our money in Redhead's.