[KingOfJericho]

I tip 20% pretty much across the board. The math is easier and the difference between 18% and 20% is a rounding error anyway. 15% is considered an insult around here and I actually get rolled eyes when I pick up takeout and put an X through the tip box and write the total (but I still do it anyway).

What I find really annoying is when you go to a foreign country where tipping is not standard and they assume that because you're an American, you will tip. It's amazing how quickly they've learned to expect it. It happened to me a few times in Rome when I left a Euro on the table after ordering a pizza and a beer.

I will also say that those who tip on the subtotal are just flat out cheapskates. What does it cost you to tip on the full amount? A few extra jingly coins? Oh, and if you leave coins instead of rounding up to the next dollar, you're also cheap.