If anybody reading this knows me or any of my siblings, you'll know that we like to sleep... a LOT.
Its not a lazy thing*, but if we go a few days with less than 7-8 hours sleep (MINIMUM) we cease to function**.
The good side to this is, I can fall asleep anywhere, anytime at the drop of a hat, the only condition that makes it a bit hard is hot and muggy air temp. But even then it'll be 10 min until I doze off, max. The bad side to this is, when I am tired, my body basically says to me 'get to a safe place, I'm shutting down whether you like it or not'. I try to avoid driving even a little bit tired like the plague, also I am EXTREMELY cranky if I'm tired, ask Wifey.
Check out this article from a Harvard Business Review blog about how much more important (short term) sleep is than even food!
Source -> http://blogs.hbr.org/schwartz/2011/03/sleep-is-more-important-than-f.html
*it totally is
**being extreme to make my point, to date none of us have actually died from less than 7 hours sleep