Why is that ndsᴉpǝ poʍu?

Many folk customs arise from the belief that the supernatural world is a mirror image or a reversal of the living world.  Creatures, such as fairies, that belong to this twilight world can often be confounded if the living do things backward, such as wearing clothes inside out.  You can find traces of these customs in cemeteries, too, where symbols are shown upside down to indicate that the person buried here has entered another world.  Upside down torches were particularly popular in Victorian times.