Serious Eats - seriouseats.com

i always tip 20% unless the person is outright rude. but even then, i decide that i am really lucky that i don't have to carry heavy trays, deal with rude customers or angry managers, or work for $3/hr and even if it is the waitress' or waiter's choice to be there, a few extra dollars may mean I can't buy a back of gum later or something but it sure is going to make their night. Tipping isn't a big deal. It's about being nice and throwing someone who works a difficult and demeaning job a little kindness. so, be "precise" about your math if you want to but if you don't want to tip, you shouldn't go to a restaurant.