I bartend on occasion where I work. Not much now, but I used to bartend a lot. I think I'm an angry bartender. So I wasn't amused at all when I closed a guys tab for him like he asked, and then he promptly stiffed me on a $35 dollar check and threw it back in my face.
I happily (or angrily, depending on how you look at it) escorted him to the door, making him feel as uncomfortable as I could.
He didn't necessarily deserve to get kicked out in the manner that I did for what his actions, but I was getting stiffed all fucking night. The guy that was buying the "cheapest beer we had" and not tipping, but promising to leave a "fat tip at the end of the night" pissed me off to no end, but I was much more sober at that point in the night so I let it slide. So sadly, the guy who stiffed me and pissed me off when I was drunk at 2am felt my wrath while the original cheap-beer-drinking-frat-boy really deserved it.
Sometimes I can't wait to get out of this fucking job. So why don't I quit? Who knows.