how does the brain make dreams feel and seem so realistic? and why do you forget some?

Question: how does the brain make dreams feel and seem so realistic? and why do you forget some?
- Keywords:
  brain,
  dream
Asked by Yasmin to Jen on 13 Mar 2015.
- Jen Machin answered on 13 Mar 2015:
  
  Some people think that dreams are the result of our brains sorting through information and making new memories stronger. Rather than the dreams themselves being important, they’re just a leftover from another important process that is happening. That’s why we don’t remember some, because it’s not important for us to remember them 🙂
  
  Dreams feel real because sometimes your brain gets a bit confused, and can’t tell the difference between a dream and real life. It tries to make sense of lots of information at once, and that’s why dreams can sometimes be very random and weird! Our brains are working hard all the time to make sense of the world we live in.

Question: how does the brain make dreams feel and seem so realistic? and why do you forget some?