In 2011, I worked in an upscale cocktail bar in London. I slung tasty concoctions, opened bottles of craft beer, fancy champagne and wine and served food to those both sitting at my bar and at tables. As with many London establishments, the bar automatically added a gratuity of 12.5% to all bills. Apparently, the gratuity was 'optional' to pay, but as it was already included in the bill, it didn't appear to be optional and folk had to take the extra step of subtracting the tip from the main portion of the bill if they did not want to leave anything additional. I found it cringe-worthy to have a tip added to all transactions regardless of effort employed. Yes, I did only earn 6 pounds an hour, but it still felt weird to have someone leave me 12.5% more for opening a bottle of St. Mungo. Some customers tipped a fiver for a bottle of champagne opened and served. Yet others (I'm thinking specifically of the 10-top hen do of Welsh girls that ordered multiple cocktail rounds and food) left nothing additional. Customers never 'owed' me a tip and I was grateful to anyone who gave. 'Thank you very much' was the usual response to customers' generosity. I have always focused on the end-of-the-night tip earnings and not stewed over each table's tip contributions. As most of us in the biz might say, 'it all evens out in the end'.
The fact that someone back in the States decided not to tip their waiter is not news; it happens all the time. That the customer in question then had to justify her no tip stance with a wee note on the credit card slip was another matter entirely. 'I give God 10%. Why do you get 18?' she wrote. My question to her would be: why do you feel the need to justify your stinginess with a question?
We who are familiar with restaurant dining in the USA know the cultural rules. If one goes out to eat, then one, generally, leaves a tip. If one never tips, regardless of quality of service, then, I'd suggest, that person wasn't 'playing by the rules', culturally speaking, and should not eat out.