Rian Johnson was "pissed off" that he had to add A Knives Out Mystery to Glass Onion's title
"There's a gravity of a thousand suns toward serialized storytelling," Rian Johnson says

If you go to your local library and pick up an Agatha Christie novel from the shelf, you probably already have a vague idea of what’s in store. There will be a murder (or 5), everyone will look suspicious at one point or another, and an eccentric Frenchman will figure it all out in the end. It would be weird (and a little insulting) if they all had to be called something like Death On The Nile: A Murder On The Orient Express Mystery, right?
Die-hard Christie fan Rian Johnson certainly seems to think so. Speaking to The Atlantic about the title of his new whodunit, Glass Onion: A Knives Out Mystery, the director bemoaned the fact that modern audiences apparently can’t be trusted to solve the mystery of which 2019 blockbuster this new film that just happens to be in the same genre with the same director and the same star could possibly be connected to.