Building Fear

I've been watching a lot of scary movies lately. Some have been pretty bad and the reason they have been bad is because I don't fear the monster. Some were because the characters were shallow and I can sort of root for them to die.

So I started to think what makes a good scary book/movie/story?

One thing that I think is necessary is something that is realistic. The fear has to be something you can understand. Some stories try to be to complex in building the bad guy that by the point you get to any fears you are tired of the build up that you are disappointed in the outcome. I think the movie "Cloverfield" is a good example of this.

Another thing that there are too many scares too close together that you get tired of being scared. Some of the "Saw" movies have this effect. So many traps that by the end when the big traps are supposed to make you cringe you are just plain exhausted. Bad thing.

A good example of building fear is the book "Salem's Lot." You have a vague introduction to the bad guy. You have a slow deterioration of the town. You have the unreliable priest. You have the characters that you relate to being put in situations that you can relate to. All of these things combine into an ending that is satisfying and makes your blood pump with fear.

I know this isn't all of the things to build fear, so what are some of your examples? What do you find effective?