Why do people dream? People dream because they aren't satisfied with the reality of the world in which they live. They dream to escape the cold confines of what is, in pursuit of a place where they can glimpse what could be. Dreams are goals and fantasies, but quite often their dreams are very far from reality and show little promise of being obtained. Yet people push on for the things that they dream not because they see that as their destination, but because the dream gives them the inspiration to continue on their journey.
The Polish writer Stanislaw Lem once wrote that "A dream will always triumph over reality, once it is given the chance." Deep inside we all believe this is true. If we work hard enough, if we are persistent enough, someday the things that we wish for will become ours. Most of us will never achieve the high goals we set for ourselves, but the goals will still have the effect of pushing our aim higher and causing us to hit a better mark than we might otherwise have managed. In the end, our hopes, goals and dreams are all the same thing. Aristotle once said that "Hope is a waking dream." In order to live successfully, we need something to strive for. In John Steinbeck's book Of Mice and Men, it is the dream of the farm and rabbits that gives George and Lennie something to press on toward. Without this dream it would have been easy for them to get stuck on Lennie's failures and the sorry plight they were in, but the hope and dream of someday owning a place of their own drives the two forward.
Everyone has a dream. Some people dream big dreams, others have dreams that are small, but everyone has something they're pushing toward. If we didn't, the cruelty of reality would be very quick to envelop our stagnant existence.