Being conscious (awake) and unconscious (asleep) are two mutually exclusive states.
The boundary between them ("falling asleep") is very pleasant. Why?
Conscious => Unconscious
Some people say sleeping is their favorite thing (or one of); but it's not really sleeping that they love, because they are unconscious and thus unaware of the state they're in; it has to be the boundary between the two that they love so much.
Going the other direction (waking up) is not usually so pleasant. Why not?
Conscious and subconscience are two coexisting areas:
Conscious ------------ Subconscious
e.g., our conscious may realize that the light turned red before we got to the intersection, while our subconscious is noting that the tree on the corner was trimmed yesterday. It may be that we have a "superconscious," too - known as "intuition" or such.
But what about in our unconscious state - is there a sub and/or super unconscious, like so:
Superunconscious ---------------- Unconscious ---------------- Subunconscious
If so, which or both? Is that where our dreams live? And why is it that in that part of our unconscious (the dream state) we sometimes seem to have no conscience?
Do we have a subunconscious and/or a superunconscious?
When we cross over from consciousness to unconsciousness, do we ever go straight into the dream state, or is a dreamless unconsciousness always achieved first (we have to get to the dream state from the unconscious state)?
BTW, I realize that dreaming is referred to as a state, but it is not mutually exclusive to unconsciousness (you are dreaming while you are unconscious/sleeping, not dreaming instead of sleeping).