When I was young and afraid of death as most people are, I was very curious about reincarnation, the thought that there might be a chance to avoid death, finally coming to the conclusion that if you're about to loose your memories, whatever "soul" remains is not really you anymore.
Sleep does that in a similar way, once you wake up its a whole new day, you forgot most things of yesterday and go on to find what this day brings you. Sometimes yesterday was extremely rough or too nice and you cant forget about it, and things that you do often transcend, but mostly its just one day at the time, one little life each day.