Some people just live in their dreams, when it gets deeper it just gets more and more difficult to wakeup. After awhile you really don’t want to wakeup. Your body is somewhere, your brain is somewhere totally different. It is even sometimes in a vacant space, it is just not in a place it is supposed to be.
Quite often it is because of the fears. The pressure and the fear, pushes you too much. To release the pressure your brain goes to a blank spot and remains there.
Sometimes it is also because you are lazy and it gets worse if you are also impatient. Your brain just runaway from any situation that it needs to do something.
Oh I hate it so much when my brain goes to the blank spot, which means I hate almost every moment of my life! When I am busy I notice it more because I need all my scenes and I explicitly notice the absence of even one!