“…because people are not frogs. If we had been frogs with eyes sitting on the side of the head, the story might have been different, but humans have their eyes smack in the front of their face, looking straight out. Evolution optimized homo sapiens for wandering the savannah  moving around a plane  and not swinging through the trees. Today this evolutionary bias shows in comparing the number of people who drive a car versus the number of helicopter pilots: 2D navigation (on the ground) vs. 3D navigation (in the air). Using 3D on a computer adds a range of difficulties…”