What have you anonymously done to a co-worker to piss them off, and no one still knows you did it?

I worked tech support in college and there was no system to keep track of the hours you worked. You got paid 100% based off of the honor system. We'd write down our in and out times every day and our boss would take our word for it. Our boss was very absent minded, so he had no idea if everyone, or even anyone, was telling the truth, but he honestly didn't care as long as you weren't abusing it. Everyone was pretty honest on their hours except for one person. He'd pop his head into the office once or twice a week and have a chat with the boss and then would write down that he worked 27.5 hours that week, which is the max you can work at my school in one week. He would never work more than 2 hours each week.

Everyone in the office really hated how he abused the system and it wasn't fair that we had to do extra work to make up for his absence and yet he still got paid for more hours than anybody else in the office. So what my friend and I started doing was the day before our hour sheets were due, we would take his sheet and shred it in the paper shredder. Then every time that they were due my boss would have to call this guy because his hours sheet wasn't in the pile with everyone else's. This guy would be too scared to tell blatant lies to my boss over the phone, so he ended up only saying that he worked when the schedule said he was there, so he'd end up getting paid 10-15 hours LESS per week because of this.

It went on for three months before he started personally turning in his time sheets three days before they were due, but it was about that time that he got caught stealing faculty members' keys and stealing projection equipment and computers from the buildings on campus. He got fired and arrested and that was that.

/r/AskReddit Thread