For example, what kind of story would Geralt the Witcher tell his kids? "Once upon a time there was some normal everyday shit that went how it always goes"?
Must be the equivalent of realworld kids saying "Daddy tell me the story about the Tesco delivery again! The one where they forgot the 2L bottle of Pepsi Max!"
"Once upon a future there will be a world where everyone has free healthcare from the government and machines exist which do the dangerous and repetitive work for us, so humans have more time to advance science and arts, as well as enjoy themselves. The end."