When I was a kernel engineer at Sun, there were stretches where I worked around 14 hours per "day". "day" had a different definition for me, I worked on about a 34 hour "day". Which meant that my day time hours were constantly shifting. A coworker put a clock on my door that said "where's larry?" and it showed when I'd be in next. I think it was a joke but some people said they liked it.
The reason I did this was I would be working on stuff where it could take ~8 hours just to regain the state I had in my head when I stopped working the previous day. So if I did 8 hour days I'd never make any forward progress. So you do 8 hours to page in the state and then you go as far as you can go to move things forward.
I didn't have much of a social life back then but I didn't care, I was getting stuff done at Sun and loved it. It was a super productive time of my life.