Patronizing service establishments is a privilege, not a right. You're always free to cook your own meals, make your own coffee, wash your own clothes, pick up all your own items, and drink alone in your living room. And the places that have added the gratuity option to their POS screens are just that, an option. You're always free to put 0%. There's a big difference between "expected" and "requested". Don't let your own guilt confuse those two words.