Virtual interfaces are unquestionably useful, but are a source of amusing anecdotes each time they fail to match the user’s intuition.
My step-father who, confusingly enough, is also named Alan, used to travel around Australia, explaining super-annuation to groups of his company’s miners, loggers, road-builders and factory workers.
Halfway though one such meeting, a gust of wind caught the edge of a slide on the overhead projector. To the audience’s delight, Alan flung out his arms and grabbed the projector screen, and then watched as the image continued to slide gracefully across the screen and off the other side.
Next tour, he got a laptop and data projector.