It's good to give people tips for their service.
Sara is treating her friends to a nice meal and notices that the restaurant is somewhat pricey.
Sara wants to save as much money as possible.
Sara orders a lower priced meal and a water to save money.
Sara decides to stiff the server on the tip in order to save money there.
The server is happy to get a reasonable tip and everyone is happy Sara bought them dinner.
The server is upset and Sara's friends think she is a cheapskate.