It's rude to make someone lose their job.
Frank's eating at a restaurant and his waiter Joan has gone what Frank feels is a considerable amount of time without refilling Frank's drink.
Frank wants to communicate his displeasure with the waiter's service.
Frank leaves a very small tip for the waiter when he receives his check, and suggests Joan try harder in the future, or she might lose her job.
Frank demands to speak to a manager and when he does, demands Joan should be fired for poor service.
Joan learns from this experience and provides better service to other restaurant goers.
Joan gets terminated and everyone else in the restaurant thinks Frank is mean.