Writing

They used to believe that REM sleep was the deepest but studies showed that dreaming periods were less restful than non-REM periods.

Our brains are very concerned with visual input while awake but in sleep all of that brain power is freed up.

A friend of mine quit smoking using hypnosis -- every other method had failed him. He was so impressed with the results that he learned to do hypnosis for his patients (he was a Nurse Practitioner). I have used self-hypnosis to ignore annoying sounds. It works in part because you want it to work.