Oh yes, I've gotten up to start the day only to go back to bed a short time later.

I think I do better on a mere six(-ish) hours of sleep. That's when I naturally wake up and feel the most alert (six hours after bedtime, I mean).

But then I convince myself I need to sleep more, so I go for another 90 minutes, at which time I behave like a groggy slug-like creature.

So why don't I sleep from 11pm to 5am? Good question. I think the answer is that sleeping is my favorite activity. If there were a fun and rewarding activity waiting for me at 5am every day, I'd probably follow that schedule.