Why do we dream? The mechanism of dreams is still unclear. Maybe after falling asleep, the activity of some organs (including sensory organs) will lead to dreaming. The content of dreams is related to our psychological trends such as expectations, attempts and worries. Experiments have proved that the content tendency of dreams can be artificially changed. For example, if you want to dream of flying, you can dream of flying after a lot of efforts as long as you meditate before going to bed, but the content of the dream has no special significance.