I usually get confused when I start to day-dream or be in deep thought. Like when I'm thinking on a certain subject a lot, my body keeps on going (that is, walking around) without my mind paying attention whatsoever. So when I finally stop and am actually conscious of my surroundings, I completely forget what happened during the lapse of time when I was thinking.
But as far as sleeping goes, I seem to have no problem with it like the other members. Though, I do tend to take 10-12 hours of sleep during the weekends.