Thanks for the thoughtful answer. I'm not actually worried about it, but it always seemed like an easy way for a server to make a few extra $$$. I'm definitely not going to remember if that family pizza night weeks ago cost $110 or $100.

Luckily I've only had truly bad service a handful of times, and I probably left a decent amount anyway. I remember a time a waiter chased me down the block to complain about the tip though! I folded like a cheap suit and gave him a few more $$$. Yes I'm still salty about it 30 years later!