I've always enjoyed the early mornings. For most of my working life, my place of work was at least twenty miles away, so my morning ride would begin sometime between 2:30 AM and 5:00 AM. That is still my favorite time to ride. It's peaceful and traffic is light.
As I've aged, I have found that I have more trouble getting to sleep at night. Some of it may have to do with living in a city that has a lot of loud people out at all hours and some may be due to the fact that I just don't ride as much or as hard as I used to so I'm not as tired at bed time. Whatever the reason, I do enjoy a nap or two each week to "catch up".