It's rude not to tip your server at a restaurant.
Sebastian just finished eating breakfast at a local diner and is getting ready to leave.
Sebastian wants to say thank you to the waiter.
After paying for his meal, Sebastian slips the server 15 dollars and says he is grateful for the service.
Sebastian pays for the meal only, and tells the waiter that he appreciates the service.
The server is pleased because this has been his best tip today.
The server is disappointed, because simply being appreciated isn't going to pay the bills.