When I had that 12 hours night shift at the microchip factory my body got all messed up. Several doctors told me I needed to get out of that job, it was actually ruining my health.
One gave me some melatonin, but it wasnt enough. Eventually I got fired for fucking up on the job. My brain couldnt focus. I have never been so happy in my life. Being free of sleep deprivation was wonderful.
I am the opposite. I'm most awake from 12noon to 4-6am I can stay awake to 9am pretty easy for a night shift. I've been like this for 5 years. In highschool it started junior year, I would go to bed at 4am, wake up at 730am, go to school, get out of school, do whatever, then sleep for 4 hours usually like 8pm to 12midnight. Then repeat.
It was great getting out of highschool and making my own college schedule. Everyone just assumes I'm lazy and I don't really know what to make of it. Working day shift does to me what sleeping night shift does to you. I can keep it up a few weeks but I eventually crack/crash.
The worst is family holidays because I miss out on sleep to do family stuff but thats okay. I wish I could wake up earlier just to be on NPT(normal people time

) but at the same time my schedule is great because It's so much more productive to be on the opposite side of rush hour and get my stuff done late when I don't have to wait in lines.