It's expected to tip a server.
June is having lunch at a cafe and the kitchen staff has overcooked her food.
June wants to express her discontent with the food.
June pays for her meal including a tip in the amount and writes a negative review of the restaurant online.
June complains about the meal while asking for the check and then leaves no gratuity.
June's server is able to make a livable wage that day.
June's server makes less money that day because of the kitchen's carelessness.