Let's say the bill was $100. Let's say tax is 6%. Let's say your dad wanted to tip 20%. Your dad is talking to the waiter over a mere suggestion of $1.20 that t

Let's say the bill was $100. Let's say tax is 6%. Let's say your dad wanted to tip 20%. Your dad is talking to the waiter over a mere suggestion of $1.20 that the waiter has zero control over. In my experience, I'd say half the bills I get have suggested tips and of those I can count on one hand how many suggested the tip on post tax amounts. I used to give an exact pretax 20% tip, just on principle, but one day just I realized it was kind of silly to worry over such little amounts. Forget principles, the day I can't afford to tip well is the day I can't afford to dine at a restaurant.