Sleep...zzzzz

Are you one of those people who can function on 6 hours of sleep without so much as a yawn the next day? Or are you like me who becomes useless if you don't have at least 8 hours of sleep a night. Why is this? Why do some of us physically need more sleep a night than others? I think that it is how are bodies are built but I'm not entirely sure. Another question that I have is why do we categorize people in two very distinct groups: night owls and the morning people? I personally will not talk to you if I don't have at least one cup of coffee in the morning. Trust me you do not want to see me in this situation. IT'S UGLY. So I guess I can be categorized as a night owl. The morning doesn't do it for me, my brain is a slow riser. I think the best at night when my brain is fully awake and alert allowing me to make sense of the countless number of ideas that bounce around in my head on a daily basis. Just something to think about what type a person are YOU?