When I first started doing graveyard shift for this one company, the guy who was training me disappeared for a few hours, then he returned with his hair all messed up. Did this several times that week, then I found out that he went to his car and took naps for a few hours each night. The following night, I did the same thing. When you wake up from that, you fee like shtt though.
Same company, when I moved to day shift, one night, after work, my wife and I got into an argument, middle of the night. I left the house, drove to work and slept there. Drove the night guys crazy. I was sleeping in a desk chair with my head leaned back so I snored like a bullfrog all night. I guess being senior has its rewards cause no one woke me up to tell me I was bothering them.
Then one day, after a visiting engineer from our parent company worked all night, he fell asleep at his desk the next day. We took pics and made a going away card for him with it.