Why is something so common so hard to describe? Partly because it is so common. We're all "awake" most of the time.
But wakefulness is not the equal of consciousness. I have had the fairly common experience of being awake but not aware per se. My mind wanders, and sometimes it wanders into a place where I am awake but not conscious. I am interacting with my surroundings as if I were aware, but when I snap out of it a few moments later, I am returned to my normal cognitive experience.
What does this mean?