No one really understands why we dream. Perhaps dreams represent signs that are happening to us that our conscious minds cannot decipher but the subconscious mind can. That is why dreams are full of signs and symbols and that can be interpreted by dream interpreters where we realize how much sense things make after the fact. Dreams can also be a way to express fears and anxieties.
However, regardless of why dreams happen, we are limited as far as what we can actually do in our dreams. And psychologists say that we cannot do the following six things as we dream: