Anybody else experience this? Why do you think? I find that I am not "on" until around 6 PM. I can function but I don't feel alive until around this time. I'm not lazy, I can work my ass off and be around lots of people, but earlier than that it is a drudgery to do either. Is there scientific basis for humans being crepuscular/nocturnal, or is it just some psychological hangup?