The Mist

This may just be the most brutal, shocking and downright cruel ending that we've ever seen put onscreen. Moments after David Drayton uses the group's last bullets to put down the rest of his companions - including his very young son - in a bout of noble mercy-killing, the army rounds the corner and saves the day. Salvation comes just a few moments too late, and Drayton pays the price for losing hope: he must live with the fact that he murdered his own son for nothing. It's dark, it's horrifying, and it's completely brilliant storytelling - swift and vengeful punishment from the gods for those who would despair when death is not yet a certainty.