It goes without saying that an ending can make or break a movie - get it right and you elevate everything that came before, but screw it up and you can fatally derail a film no matter how well-crafted it might otherwise be.
And there's nothing like a movie that teases one ending only to ultimately go in an entirely different direction.
Sometimes our expectations can be subverted to electrifying effect - Captain America: Civil War teasing a showdown against a supersoldier army only to cancel it last-minute, for instance - but doing this in a way that doesn't disappoint is extremely challenging.
After all, movies are all about wish fulfillment, and if you tease viewers with a tantalising finale only to deliver something else entirely, it needs to be damn good.
And that's where these 10 movies - some of them good, some of them bad - all came unstuck.
Each promised a spectacular and gratifying ending only to serve up a woefully inferior replacement, demonstrating a certain creative cowardice or, in the very least, sheer laziness...