(One little aside to Gerard: Guess who's sitting here quaffing hot-pepper martinis?)
This is an interesting topic in that everyone is affected differently by the stimuli that horror provides. The world at large tends to equate the term "horror" with Freddy Krueger, Michael Myers, and Jason Voorhees, with an occasional nod to Stephen King (in other words, sneering at the whole concept); indeed, the horror field is the ghetto of "serious" literature, oftentimes deservedly. When horror is handled poorly by its creator(s), it rates as one of the lowest forms of entertainment on earth. Almost as low as rap/hip-hop (let's see if THAT opens a can of worms). Nowhere outside the horror field, perhaps, is Ted Sturgeon's postulate that "90% of everything is crap" more graphically illustrated.
I think there is a place for graphic horror; but in small quantity and as a complement to a theme--not as the focus. For example, the original TEXAS CHAINSAW MASSACRE, for all its cheapness and campy style, has a neat little undercurrent of authentic dread running through it (in fact, there's almost no gore in this movie; it's all done by suggestive camera work). Clive Barker has produced some effective material, both literary and film, although he tended to lose focus about 3/4 of the way (to be generous) through everything he wrote during the late 80s through the early-to-mid 90s (I haven't read any of his later work and can't comment upon it). There's a lot of "shocking" horror that has some merit; but the key is in the effect of its execution. And very, very few people have done it well.
Good horror, as in all fiction, requires an emotional connection with the characters, and in horror, it's easy to lose that connection because of the prerequisite need to suspend one's disbelief. As soon as a story goes over the top, it loses its audience if it doesn't provide something or someone to connect with on an intimate level. To agree whole-heartedly with Raineypark, this is why action-adventure films--characterized by the typical fluff of Jerry Bruckheimer, John McTiernan, and John Wu--rarely appeal to me.
The 1990s adaptation of THE HAUNTING characterizes just about everything that's wrong with the horror genre. And like Gerard said, you can predict every moment of a Jason or Freddy film down to a beat. Effective shock depends on effective suspense--for the very reason that "shock" requires nothing more than making you jump; anyone can do that. And most fright flicks just want to make you jump rather than tremble first. It requires considerably less brain power to induce a shock.
I detest the ubiquitous quip that audiences of today are "more sophisticated" than they used to be. What a load of crap. By and large, audiences today might be able to identify CGI, and they might quibble with a made-up iguana masquerading as a Tyrannosaurus, but they've lost a lot of their imagination. They laugh at the original, classic THE HAUNTING while extolling the virtues of the newer one's special effects, but that's because they've come to expect every detail being spoon fed them. The sounds of the reverberating booms through the halls of Hill House, without apparent source, are a thousand times more frightening than a silly pendulum whipping out of a fireplace to knock the head off of an unsuspecting actor. People nowadays are much happier with the avenging ghosts of wronged children than an unknown, inexplicable thing that might not be a ghost at all because they have a pat explanation. There's no need to engage the brain and ingest, interpret, and otherwise interact with the story.
Actual horror (not to be confused with terror) is the realization of sheer futility in the face of something beyond acceptance, whether that thing be supernatural or as human as you or I. You might know horror when you realize you are going to die because you are a passenger in a plane that's about to crash into a building. You're completely helpless. Worse, you're either a pawn or merely insignificant to the force that has devised your end. That idea, to me, is the appeal of Lovecraftian fiction, with its accompanying mindless, ambivalent, but altogether destructive entities; there's no more reasoning with them than with a shark. Yet there is purpose behind them. They aren't just there to make you jump out of your seat.
Exploring the emotions of horror and terror generate adrenaline; I think that's why many of us enjoy the genre. I think a lot of my interest in horror derives from the same source as my enthusiasm for roller coasters. But for the roller coaster to be effective, there has to be a gradual, logical build-up before the great descent. The big hill is the not the whole experience; just a part of the ride.
Lastly, since in most horror stories, death is involved at one point or another, there's hardly a better field where religion and philosophy can be explored at their farthest bounds. After all, we're all going to die. There's a certain fascination with that idea. Few of us know how we're going to die. In a story or movie, if we're engaged with a character and he faces a ghastly fate, we're there with him. If the [writer/actor/director/insert appropriate creative individual here] has done his job, for those few moments we experience the same thing vicariously. We're engaged emotionally as well as intellectually. To me, getting both is what good horror is all about.
