Generally speaking, audiences expect a movie to deliver a satisfyingly concrete ending which ties off all the hanging narrative threads and resolves any major mysteries.
But there's certainly pleasure to be had in ambiguity, in a story which refuses to give viewers all the answers they're expecting, but rather leaves them to meditate on the mystery forever more.
While films that refuse to commit to a hard ending can absolutely come off as cowardly or unimaginative, when it works, it really works.
And so we come to these 10 films, each of which eschewed a more conventional, defined ending in favour of one you were left to figure out for yourself.
Though in each case there are at least two clear possible outcomes, the scripts don't come down on one either way, leaving audiences to decide for themselves which one makes the most sense.
Even if you pore over these movies dozens of times, they're so expertly calibrated to be ambiguous that it's difficult to categorically say what the true outcome is one way or another.
And that's a sign of a great storyteller at work...
10. Martha Marcy May Marlene
Martha Marcy May Marlene stars Elizabeth Olsen in her stellar film debut as Martha, a young woman who has been living with a cult for two years and, upon deciding to leave, struggles to pull herself away entirely.
Even when exiting the cult and living with her sister Lucy (Sarah Paulson), Martha has PTSD-induced delusions that the cult's members are pursuing her, leading to a climax where Martha finally agrees to be taken to a mental hospital.
As Lucy and her husband Ted (Hugh Dancy) drive Martha there, however, Martha notices a man she spotted earlier in the day get into his car and seemingly follow them. Martha looks out the back window of the car and then the film just... ends.
The whole point of Martha Marcy May Marlene is its ambiguity, namely that Martha is an unreliable narrator and we as the audience have no idea if her perspective is correct or delusional.
Whether you believe she's reacting to a fantasy or is indeed being followed by the cult, they're both completely valid readings sufficiently backed up by everything leading up to that point.