One rule in 3D production or post is to take off the glasses. There’s a lot to see in the overlap of images.
On the other hand, if you have a 2D movie in front of you, close one eye and a lot of the 3D detail comes out. You get back some of those 3D cues/clues that the eye/brain complex merge when two eyes are open and staring at a flat screen (and realize “Hey–dis be flat!) – clues like occlusion, size of familiar objects, size of comparative objects, texture detail, distance color shift, haziness, all get un-merged.
Un-Merged is how Harry Potter will be delivered on November 19th.