Whatever the reason for sleep, everyone sleeps and everyone dreams every night. Many times we don’t remember our dreams, but we still dream. Like sleep, no one knows exactly why we dream or what dreams mean. There have been many theories about dreams throughout history. Many cultures believe that dreams can predict the future – that they can tell us what is going to happen to us. Sigmund Freud and other psychologists and psychiatrists believe that dreams can tell us about our feelings and desires.