Got loads from my few years at Sainsburys:
Went to Homebase in my uniform when it was owned by Sainsburys to buy some wood to make a speaker shelf in my car, got fed up of waiting for the guy top cut it so I went and found a saw and cut it myself, was stopped after I had just finished and told I counldt do that, to which I replid well I just have. The next day the HR manager tried to tell me off but couldnt stop laughing at what i had done.
Had a big egg fight in the chiler with 3-4 other people, and then told the manager I knew nothing about it.
Me and a mate used to send people to isle 30 in a 20 isle shop when they asked where a product was.
My best prank was to wrap my collegues desk in Xmas paper whilst he was on holiday, I wrapped everything, screen, PC, mouse, keyboard, cup, chair, desk, phone, everything, the guy was a jehovah witness so it was pretty funny, this was a return prank after he has removed every item off my desk when I was on leave.
We had a guy in the office who never ever cleaned his cup, it was disgusting, so once I cut out a circle of grass and put it in the cup, another time we placed hazard warning tape all around his cup and desk.