I took a party of 12 out for dinner at an expensive New York restaurant - we had some serious wines and the bill came to just over $5,000. I thought a $500 tip for indifferent service was more than generous. The restaurant manager didn't and we had a stand up row at the end of the meal. I didn't budge and would never go back.
Off topic, but wanted to share the experience.
Tipping is clearly a way of restaurants paying their staff less. Not my problem.