Maladjusted Monster Munch: Developing Doomed Characters, Part I

In many genres of horror, one of the essential plot elements is character deaths. The practical consequence of this for the author is the necessity of writing characters who will essentially end up as cannon fodder to move the story forward. 

Depending on the story, one can sometimes get away with minimal development of the 'cannon fodder' characters-- the audience is aware their only role is to get picked off one by one, and in early horror movies that's often the case. However, there is an increased expectation that there be some level of character development in horror (or similarly action-oriented genres).

Perhaps because of the desire not to get attached to characters who are toast anyway, or perhaps harkening back to some of the moralism in certain subgenres of horror, the character development goes in the direction of making the leads seem like thoroughly unpleasant people. 

In and of itself, this is not a bad trope. In fact, it can be used to create a sense of schadenfreude regarding the messy ends of the characters in question. Give us a set of really despicable characters, and we feel okay about being entertained as the monster turns them into a midnight snack. Done right, it can also give an extra layer of conflict to the story if the protagonist has to struggle against obnoxious or inept characters as well as the supernatural horror.

Alternately, deeply dysfunctional characters struggling against the source of the horror can re-introduce the element of morality and add another layer of emotional depth to the story. When the internal conflicts of the characters interact with the external plot and create more complications, it increases the overall suspense. This can also be used to amplify the plot events by having inner and outer conflicts mirror each other.

That said, characters who are unsympathetic while lacking interest or complexity are a quick way to lose audience investment. Be careful that your characters aren't just dysfunctional for dysfunction's sake, but that their problems advance the plot