Why do we dream? there are many theories  on why we do, but none of them are actual proven facts. There is Freuds theory which says that that dreams carry out hidden hopes, desire, 'dreams'. Another theory (Jungs' theory) says that dreams carry out a meaning, not always our desires, but these dreams can be interpreted by the dreamer to find out the hidden meanings and symbols. Another theory (Cayce theory) says that deams are our bodies awy of building up of the mental, phsical and spiritual well-being. Another two theories became and argument.
One of them, the Evans' theory says that dreaming is our badies way of storing the immerse array of information gained during the day, wheras the other theory (The Crick and Michinson theory) state that this information is being 'Dumped' rather than being stored. Nobody really knows which or whether these theories are true, but from these, we may decide for ourselves which we agree to or believe in, and they may help us to understand our dreams much more.