I'm both a morning person and a night person. That's not a great thing because it involves some very short sleeping times, which can mean I'm tired either in the morning or at night (or both); which, in turn, means I'm neither much or a morning, nor a night, person on some days. Then again, I can be great with very few hours' sleep and with being awakened when I otherwise may have done better with some more sleeping.
With enough sleep or without it, I tend to hate (and not be at my best at) the hours between 3:00 p.m. and 5:00 p.m. Somehow, those seem like hours when the afternoon has become stale (and so have I). :/