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  1. 166%: I gave a $20 tip for a $12 bar tab once to a favorite bartender on her last day before quitting to become a full time masseuse. —Chris Kubica
  2. @fats once gave a waitress $45 on a $55 bill because she asked if we wanted any 'beerssert' (beer / dessert). He really likes word puns.
    Suggested by @dev