I used to train at what was primarily a mma gym the boxing coach there was good had a lot of amateur experience but it was mainly young kids, an 2 or 3 guys who were about my age and size and a polish heavyweight who was about 6'6 240lbs but not very good. I'm only like 5'8-5'9 and at the time about 150lbs.
So as you could imagine the sparring was quite limited, we only had the one boxing ring and an mma cage for sparring which had a cushioned floor so when we boxed in there we had to take our shoes off (This meant it did get a bit slippy if the floor was wet.)
One day I was sparring with the polish guy in the mma cage (it always looked like a low level haye and Valuev when we sparred ) he stepped in to throw a jab to the body I stepped off to the side and caught him with a cuffing left hook there wasn't much in it but he slipped ended up on the floor the coach tony looked round and thought i'd dropped him.
I didn't really like the guy so when he protested that he slipped to everyone I just took the mick out of him and kept saying stuff like '"it's ok everyone gets caught sometime' etc etc
I changed gyms about 2 months later to a proper amateur gym but just about everytime I went in the gym after that day someone would mention it to the polish lad.
I never did tell anyone else in the gym he slipped.