It always began as an ordinary dream. But at some point Mary Poppins would fly overhead on her umbrella, look toward the “camera” of the dream to deliver a cackle, then fly off, turning whatever pleasant fantasy I’d been having into terrifying chaos. Everything in the dreamworld became darker; trees died, I got lost and left behind in a grim landscape, and I fell victim to all sorts of other horrible things I’ve managed, thankfully, not to remember so clearly.