" The normal sequence is that energy is prompted at the perceptual system, passes into consciousness, and thence to the motor system, where it is discharged by action. (I feel an unpleasant sensation, realize that I have been bitten by a mosquito, raise my hand, and swat the insect.) But in dreaming energy flows the other way. Barred by the censor from consciousness, and hence from discharge through action, wishes flow back, collecting unconscious memories on their way, and present themselves once again, now transformed by the dream-work, to the sleeper’s lowered consciousness. "

― Sigmund Freud , The Interpretation of Dreams