Fear of heights, fear of spiders, fear of flying, fear of death–everyone is afraid of something. And these pop-ups place you in the hot seat–whether it’s the dentist’s chair as the drill comes spinning toward you; looking over the edge of a skyscraper whose sheer face plummets thousands of feet to the sidewalk far below; or the window seat of a plane as the oxygen mask deploys, your drink spills, and the horizon line shifts to an angle that is suddenly, terribly wrong . . .