I seem to drift off and become less lucid, to the point of becoming a cloud-cockoo-lander. I often say things which make sense to me but have no connection with other peoples reality at all. Oddly enough, I never become irritable through sleep deprivation. Making an accidental double entendre is common, making for some awkward moments I am totally oblivious to.
In shorthand: I become a resident of cloud-cockoo-land, at least in spirit (I'm prone to this anyway.) Can be cured with a longer-than-normal sleep. (I've been known to sleep for 14 hours straight before.)
PS: Great new thread by the way, a lot better than my first.