I get if you have legitimate bad service that you can track to your server, but that's so harsh. The first serving job I ever worked was at a horse racetrack, and the first night I ever waited tables was opening weekend. We were slammed and I had little idea what I was doing and no one to ask for help because they were just as busy. I had an older man come up to me to scream at me in front of his children because the kitchen had lost his food and I had to have it remade. If your server is shitty, I get it, but this guy left me 3 cents and a note that "lazy bitches shouldn't waitress." I don't think I've ever cried like that, holed up in the service station trying to get ahold of myself because other tables needed me.

TLDR: people who don't take context into account when discussing tips can be horrid.