The best, and scariest movies actually ask us questions we'd rather not even think about.
Oldboy (2003) asks if vengeance is worth death and the torture of knowing the truth, in all its unvarnished majesty?
Pan's Labyrinth (2006) asks - is it better to die in a fairytale then to live in a dark reality?
The Diving Bell and the Butterfly (2007) asks what happens when only the mind, and the mind alone remains?