I am lucky that I live alone, so no one to dictate my sleep. And when I visit my mom, she is much like I am, so there isn't any Sleep Dictator-like behavior. I used to be a morning person; I'd get up, and be on my merry way, Sundays were laundromat day, which opened at 7. I'd go, put my stuff in, then walk across the street and get coffee and breakfast, and be done and back home before 9! And on Sat I was up and out doing errands since I prefer to be out and back before the masses.
However, for the last 7+ years I've had a second job so I'm always tired. I am no longer a morning person, and am quite unpleasant without my coffee. Not mean, but just foggy and unable to concentrate or speak in complete sentences. I'm more of a night owl now. But like others, I can't go to bed earlier than my "normal" bedtime, or it throws me off, unless I'm sick. My normal time is between 11-11:30 - although I have been known to stay up until 12:30. Last Sat I was in bed by 10, and wide awake at 3:15.
My problem is sometimes I don't get home from my second job utnil almost 10, and I need at least 2 hours to unwind and decompress. I will also get caught up in a game, book, etc. and won't want to stop and go to bed. So then I'm tired the next day. And on the other end, it takes me a couple of hours to get going and become functional in the morning. I do ok for work, but on weekends, rather than sleeping in, I prefer to get up, have my coffee and "putter" for a couple of hours. this way I still have most of the day, and I get to wake up on my own schedule.
If I do sleep in late, I still need that putter time, so by the time that's done, the day is half over.