It's inconsiderate not to tip for good service
Ken is footing the bill at an expensive restaurant and is worried about the cost.
Ken wants to save some money on the food bill.
Ken eats only an appetizer and doesn't order dessert to save money.
Ken ends up leaving no tip in order to save on the pricey bill.
Ken's server is relieved after service because the tip was much needed.
Ken's server ends up not making enough money for the day.