I've been a bit miffed by tipping culture recently. I ate in a restaurant with my wife and her family last week. I said I'd take care of the tip. I put a fiver on the table while I searched for more money and my sister-in-law said, "that'll do". I thought a fiver was a bit measly so I added another fiver on. It turned out the bill came to £170! In what situation would five pounds be a good enough tip for $170? Both the food and the service was excellent. If I'd known how much the bill came to I would have put in another tenner.
I've noticed a lot recently that people I eat with don't tip. I think that's pretty insulting. I'm not a mad 20% tipper but try to leave at least 10%.
tl;dr? How much is an acceptable tip in a restaurant?