What Happens When You Sleep?

All human beings need, i believe, an average around eight hours of sleep. People whoe sleep deprive, they don't o function properly cognitively. Most of these dreams we forget and why do we forget that? That's also a good question. Neuro science is very imperfect. I would not even call them science. It's a lot of hand waving. Why do we experience certain events in dreams? Some people have the same dream over and over again?"