I like the concept about how a person sleeping at one place can be at different places quarrling , smiling , eating food , doing something crazy , moving to places where he has never been , being with your loved ones .....
Nightmares are the worst , even if a person is sleeping taking rest obviously having no motion at all ...his heart starts to beat faster ,faster enough to make him wake up...
I have been doing some research in dreaming myself and i came to know it is better to sleep while leaning on the right side...