Reddit, how do you subtly fuck with your coworkers?

1. I teach elementary music. Once, I had a rivalry with the gym/PE teacher. She would send the kindergarten class to mine and tell them it was my birthday and I loved birthday hugs. She would do this about twice a month. I sent them back to her and told them she loved it when people would step on her foot. They rushed her and started stomping. She also told the kids to go into my class, say nothing, and just stare at me. It was the creepiest damn thing. She won.
   — Jabez77


2. Found a little script a while back that would randomly open and close the disc drive on my coworker's computer. Not incredibly often, but enough to the point where it was annoying. He requested a new computer, I reinstalled the .scr as soon as he left that day.
   — SnaggyKrab


3. Made a new folder on his desktop called Russian Dwarf Porn and then took a screenshot. Set the screenshot as his desktop background. For an engineer it took him a ridiculous amount of time before he realised why he couldn't delete the folder.
   — Pineapplespaceman






4. Everyday I would get into the locker room before him and place one penny in his right boot. This went on for 2 months. After about a week and a half I could see him getting frustrated. After a while it just became the norm for him to shake the penny out of his right boot everyday. He wasn't frustrated anymore, he was defeated, and just accepted it now. So, one day I decided to put it in his left boot. He came in shook his right boot out like usual, but nothing fell out. He looked so relieved, like a huge weight had been lifted. Then he put on his left boot on, and just fuckin lost it. He slung that boot across the locker room with all his might, cussing and calling out whoever did this to him. I stopped fucking with him after that. I plan on putting a penny in his boot once a year from now on just to remind him. Nobody knows it was me placing the penny and I plan on keeping it that way. EDIT: spelling. Thanks.
   — GeronimoEKIAx2


5. On a windows machine, go into the mouse settings and enable "Click Lock". This changes a primary button click into a toggle on/off instead of the standard press and release for highlighting and click and drag operations. It's infuriating as hell and obscure enough that most people assume the mouse is broken and will request a new one. The new one will do it too. Or just microwave some fish.
   — Gromit1710


6. I sit beside a guy who is a good friend of mine and our desks are separated by a moveable divider. Since I moved beside him 2 weeks ago I've been moving the divider a centimetre towards him each day. We're at 13cm and he hasn't noticed yet. I have to shift his monitors soon though so that will be interesting
   — Nelfoos5






7. Our old HR director was notorious for having a messy desk. My manager and I made it our mission to add an additional 1,000 random sheets of paper to his desk over the course of a few weeks without him noticing. Every morning he'd come in and 10-15 more sheets would be added to the mess. It took a long time for him to suspect something was up.
   — beagle_dog


8. Gradually increase the pressure required to open the office door by adjusting the automatic door-closer with a screwdriver so they become accustomed to giving it a mighty shove then one day disconnect the arm altogether.
   — FuckCazadors


9. I plant evil questions in their lectures and tutorials, seeding them to students we have in common. I've been doing it for years, and they have no idea it's happening. They're just constantly baffled that the same kids each year keep asking obscure, graduate-level, often borderline unanswerable questions in person, but never quite manage that level of insight in their writing.
   — varro-reatinus