When I worked at a golf course once there was a guy who worked there for a short time who smoked with us quite a bit.
To make it short, one day he just stopped coming to work and was let go.
I see the guy at a friends house later and he says he can get me some weed.
He brings me back a half ass bag filled with a bunch of stems and seeds and tries to tell me its some "fire ass shit."
I know this guy probably took half of this shitty bag and thought I was too naive to know what I was supposed to be getting.
Never the less, after an evening of excuses and sob stories we parted ways, but I still felt like a dumb ass who had been had.
So I go into my bosses office a few days later and take his last paycheck. I drove down the road and threw it out the window. Im sure they just cancelled the old check and issued a new one, but it probably took him an extra month or so to get paid
Not exactly the ultimate revenge, but just enough to piss someone off and put a little stress in their life