A dream is a succession of images, ideas, emotions, and sensations that usually occur involuntarily in the mind during certain stages of sleep. During a typical lifespan, a person spends a total of about six years dreaming. Most dreams last only 5 to 20 minutes. Dreams are basically stories and images that our mind creates while we sleep. They can be vivid. They can make you feel happy, sad, or scared. .Dreams can happen at any time during sleep. But you have your most vivid dreams during a phase called REM (rapid eye movement) sleep, when your brain is most active. Theories about why we dream include those that suggest dreaming is a means by which the brain processes emotions, stimuli, memories, and information that's been absorbed throughout the waking day. Where do dreams come from? “Activation-synthesis hypothesis suggests dreams are caused by brainstem activation during rapid eye movement (REM) sleep and stimulation of the limbic system (emotional motor system). ...