That happened twice on two camping trips actually, my tent was uncomfortable and the wind outside was always loud. Surprisingly I wasn't falling asleep at all during the daytime.
Yes, and that was after going hardcore with exercises without water for 20-30 minutes during taekwondo practice... (or perhaps I'm overexagerrating about the amount of water)
Ever mistook a person for one of your friends or family just from looking at his/her back?