The Hero’s Journey.
Who takes a shopping cart home from the supermarket? When does it reach the level of ‘Quest?’ (And who takes a shopping cart home when it isn’t the apocalypse or post-apocalypse?) Who threatens to get in the way? The fifteen year-old charged with wrangling the carts together and returning them to the store, imagining them as millipedes filling the streets as he does so? (Or a set of octopus legs in search of a body?)