Narrator: He's wrong.
Source:
I think there is a fundamental misunderstanding about tipping in America. Diners have been led to believe that tipping should be based on the quality of the service. But this is not the reason we tip.
I think diners need to ask themselves a basic question: Do you get paid when you're having an off day? When you're not at your best? When you're in a bad mood?
What's more, waiting tables is hard work, and servers are only human. They may be having troubles at home, or they may be worried about a loved one. Or maybe they're just spacing out. Who among us has not done that at our desks?
Bottom line: Diners should always tip 20 percent. Always.
If the service is terrific, you should add more to the tip. But never subtract from the 20 percent.
Source: