Alright... I'll join, only because I make the conscious decision to stay awake during the night/early morning hours. I feel more at ease in this state, even if I am left with little to do or no one to converse with. I am much more productive without the hustle and bustle of daywalkers, and I much rather see them when they are tired in the late afternoon.
In truth, I can fall asleep at any time I desire, and I sleep soundly for a duration of at least nine hours if left undisturbed. If not, have no worries, since I can still function normally and with little fatigue if I get as little as four-five hours of sleep.