Just slip a tip on the table as you leave. If the service is bad, leave little or nothing. You can also add it to your credit card bill as you sign out. It's very simple. Noone will be standing there with their hand out.

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"Only two things are infinite, the universe and human stupidity, and I'm not sure about the former."
- Albert Einstein (1879-1955)

"God is a comedian playing to an audience too afraid to laugh."
- Voltaire (1694-1778)

"I shall not waste my days in trying to prolong them."
- Ian L. Fleming (1908-1964)