8. Gone Girl
If there's any other movie that will turn you off marriage quicker than the Dunne's broken relationship, it remains to be made, as these pair have some seriously f*cked up problems that they work through in David Fincher's breakdown of two toxic people.
What starts out as a movie of Nick Dunne murdering his wife Amy in cold blood soon unfurls into a much different story, one that plants Amy firmly as the mastermind of an incredible crime scene. And instantly, doubt is cast over both stories as to what, and who, we can really believe.
Gone Girl posits that there is two sides to every story, but not that either of those sides are inherently trustworthy, or even true from their own subjective standpoint. Nick says he isn't a cheater before a girl that's definitely not his wife comes in for a surreptitious sex session, and Amy of course claims to be dead whilst very much alive.
That means we're taken on a ride as each party makes unexpected choices, with Amy's pregnancy at the end of the film - after she's lied, killed, and manipulated her way back home - the second heaviest hitter of Gone Girl's plot twists.