9. MacReady Is Rescued, Takes A Blood Test - The Thing (1982)
John Carpenter's The Thing boasts one of the most legendarily nihilistic endings of all time, with "survivors" MacReady (Kurt Russell) and Childs (Keith David) left stranded in the research station's burned-out remains, condemned to freeze to death while unsure whether the other might be playing host to the titular extraterrestrial lifeform.
Carpenter shot multiple endings for the film and the climax was a major point of contention between the director and Universal, who desired a more crowd-pleasing ending in which the Thing was unambiguously defeated and MacReady confirmed to survive.
As a result, Carpenter shot a squeaky-clean happy ending where MacReady makes it to another research station, is rescued, and takes a blood test which confirms his humanity.
Yet Carpenter felt this ending was "cheesy", and given that none of the endings fared particularly well with test audiences, he surmised that the film probably wasn't "heroic enough" for mainstream viewers. And so, Carpenter deferred back to his bleaker original vision.
Now, while there's little arguing with Carpenter's judgement in this case, it'd still be fun to see that happier ending at some point, perhaps on a future home video release - unlikely though it is.