Any gamer who has spent a significant amount of uninterrupted time staring through a 2D screen into a 3D game world understands the strange perceptual shift that takes place when returning to the truly 3-dimensional space of the real world.
There is a disorienting effect, a sense of unreality, in coming back to a place where perspective changes are achieved not by the subtle movements of an analog stick, but by actually shifting the head which houses your ocular apparatus.
