I'm a New York, and I always tip 20%. It doesn't matter what the quality of service is like. I think it's my social responsibility. waiters and waitress earn very little here often it's only a little over $2 an hour. Nobody can live on that. And the government knows they receive tips in cash, and it adds 12% when it calculates their income tax. So if a customers tips 10%, the waiters or waitress must still pay tax on 12%. Every society has its own customs for tipping. It's not that one country's system is better than another. It's just they different. If you're in The United States, I think you should tip 20%