Consciousness
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?
Probably just a visit by the Alpha Wave level. Most people have such periods and often report them as being on autopilot. Really paying attention to such things can make me curious about personhood and awareness, like the time I lost my ability to form new memories for a few hours. https://steemit.com/life/@baerdric/the-day-i-lost-my-memory
how would a bird describe air?
How would a fish describe water?
To be literal, neither can describe anything. This ties to my point. Why do humans have conscious reactions at all? Philosopher David Chalmers calls it the "Hard Problem."
Humans are not the only ones who are conscious. I'd hazard to guess that consciousness is necessary for emotions...and Ive for sure observed my cats display a wide range of emotion. They KNOW who they are...they ARE conscious of their own individual existence.