The most idiotic thing that could have been invented is a virtual keyboard of rectangular shape in the air. Like, you can very naturally control the interface with your eyes and fingers, but to enter something manually, you have to stretch your hands forward and aim at these circles.
Now, if the keyboard could be split into two halves and thrown anywhere - that would be cool. You sit on the couch, put your hands on your knees, a half of the keyboard on each leg, set up a comfortable layout, added some more additional buttons on the sides, and no problems at all.
But this rectangle in the air - total nonsense.