Fight Club (1999)
The second easiest and laziest thing in the world right now would be to make some point about how it would be the easiest and laziest thing in the world right now to joke about the First Rule of Fight Club. Which is to say, I'm beaten before I start whatever I do because this movie has, in the more than twenty (twenty!) years since its release, sewn up all the discourse. Everyone knows what the first two rules of Fight Club are, even the people who have never seen it. And the film is firmly in that peculiar category of movie which is undeniably great but shouldn't ever be anyone's favourite movie.
Obviously there are spoilers, but the likelihood is that if you get any distance into this, you've probably seen it (or read Chuck Palahniuk's book, or both, but let's face it, it's more likely you've seen the movie) so there we are.