Dreams can range from ordinary and realistic to the fantastic and surreal. Human beings have always attached great importance to dream, which have been variously viewed as windows to the sacred, the past and the future, to the world of the dead. Dreams have provided many creative solutions to intellectual and emotional problems and have furnished artistic inspiration.
The most famous theory of the significance of dreams is the psychoanalytic model of Sigmund Freud, in which desires ordinarily repressed because they represent forbidden impulses are given expression in dreams, often in disguised or symbolic form.
In general, dreams are thoughts that a human has in their mind while they are asleep. Many people have argued over time about what exactly what a dream is, but it has never really been clearly defined beyond thoughts while one sleeps.