Why do I always appear as a bystander when I dream, watching another person perform something unrealistic and no one can see me in my dream?

I think it's because dreaming is an imaginary movement of the brain, which can only be done if the brain gets enough rest during sleep. If the person in the dream can see you, doesn't it prove that the dream is done by two people at the same time? Because only in this way can the two sides see each other, or prove that this dream is true, and both are possible.