This is also the perfect term to describe why you look like yourself in your dreams (at least most of the time).
I experienced this for the first time when I cut my hair. I'd had long hair, past my shoulders for a few years, and decided it was time I stopped looking like the front man of a hair metal band. For a while after that (as I'm sure many of you have experienced) I often didn't recognise myself straight away in mirrors. Anyway, a few nights after the chop I looked in a mirror, and lo-and-behold, my hair was long again. I stood there for awhile, and suddenly realised I was dreaming.
This is called lucid dreaming, and can give you complete controll over the dream environment. (At least that's the theory - for some reason I decided to jump out a window, and I woke up.)