Yes, there are a few actual theories of the technicalities made by psychologists, but I'm interested in your imagination. Bring the impossible to life.
What determines what kind of dreams that we have? Do we have to dream? Is it necessary to survival? What about controlling them? What do animals dream about? How do dreams differ from childhood to adulthood? Can dreams be premonitions?
Leave your response in the comments, or take it and run!
picture courtesy of Google images, although it looks a lot like my cat (: