E-mail, in response to this:

Horror stories are effective when they successfully undermine (or enamble you plausibly to suspend) your belief in a rational universe.  A staple of the genre is a character who is in denial about a horrific reality until it overtakes him.  The genre is a rebuke to rationalist hubris and complacent materialism.  It operates in a universe that is mysteriously open, liberating the reader or viewer from the oppression of quotidian rationalism (and the pecksniffs who enforce it).

BONUS: Here’s William Shatner on the Twilight Zone, in the climactic scene from “Nightmare at 20,000 Feet.” You gotta love the shaggy dude.