Well, I was going to do the rant on D&D stereotypes, but I didn’t really feel like it. I felt like doing this instead.

1) When writing from their point-of-view, remember they really believe in whatever views they hold.

Too often, when an author writes a frustrating character, I became aware of a little authorial ‘wink-wink nudge-nudge,’ similar to the kind of things that a lot of people do with coy foreshadowing. Say you have the heroine’s naïve sister. She says something like, “But I can’t possibly be wrong!” 100% certainty is set up as something the author absolutely won’t allow to remain, no matter how many reasons the character might have to think she’s right. Instead, doubts and true, real certainty that the author doesn’t topple alike belong to the heroes. They and they alone have the privilege of forming conclusions that the story doesn’t invalidate.
This is annoying. Yes, a character who blindly insists on the opposite of what the heroine believes to be true (say that the character is a fanatical religious type while the heroine believes in religious tolerance) can make the audience long to reach through the pages and slap her. But that should not extend to the author taking the heroine’s part and making the frustrating character sound stupid. That’s outright favoritism for the protagonist. Instead, why not establish a continuum of opinions that could be right or could be wrong, and let the story will out or eliminate a number of them? Or why not leave some up in the air, and the audience to make up their own minds?
It’s also annoying because it punishes the character for holding a belief that she can’t help but hold, since the author created her to hold it. Remember that, in the process of creating the people who win and the people who lose, that the people who are destined to lose can’t know it, or why wouldn’t they switch to the winning side? Insinuating that they should know their beliefs are wrong and change sides, and then writing the story in such a way that they can’t, is usually a form of revenge-mongering. The author is probably creating people who resemble bullies or proponents of a belief that she encountered and disagreed with in the past, and it’s not fair to punish them for the mistakes of the people she wishes she could really get back at.

2) Switch from one POV to another.

If the viewpoint character is only in one part of a story, such as with one party in a fantasy novel with wildly divergent threads, or is a POV character among many, then you can leave when she gets too annoying. Restrict the main characters’ interaction with her to what helps the story along, whether it’s to be funny or to provide information or to create friction when they argue with Ms. Frustrating. The longer you remain in the character’s presence, the greater the temptation may be to do a ‘wink-wink nudge-nudge,’ or start dropping hints that the character will be punished, which can ruin the suspense.

3) Put the frustrating character through events which will change her.

Too often, the author creates a static character who can’t change, when really, she should be as fully human as anyone else. Need her to retain her stubbornness or innocence or fanaticism or whatever else makes her so much work to write until a certain point in the story? Fine. But what happens after that?
If the character sees her beliefs shatter in front of her, she may well go through a crisis of faith. Those are usually reserved for the heroes, but there’s no reason a minor character couldn’t have one. Sometimes it’s an event like this that rescues the minor character, and turns her into a deep and compelling person, even if not in the position of a protagonist. Why not drop her into the snake pit when she’s served her “function” in the story, and make her an end in herself? Authors are willing to do that, and just about anything else, for their heroes. I’d like to see more of them do it with their non-protagonists.
Change a character, make her an end in herself, and she can change the plot in whole new ways. The one thing I’d caution an author doing this to be wary of is that it’s easy to make the conversion to a new way of thinking (often the author’s) too superficial. The “crisis of faith” ends the moment the heroine speaks to the doubting character, for example. Have them question a little, or, if they embrace the new ideas, go as far as they did originally and become as annoying in a whole new way. In fact…

4) Put some frustrating characters on the heroes’ side.

Other than the doubts the heroine might have about whether she’s really worthy of facing the Dark Lord/saving the world/ruling the world/etc., there’s not a whole lot of questioning the heroes’ ideals. They just happen to be remarkably like twenty-first-century transplants moderate and calm and ideal and sane. If a fanatic does show up in the story, he or she is always either an open enemy or really a spy. (The number of loud and offensive people on the “hero’s side” who end up working for the Dark Lord is really astounding. It makes it seem as if the heroes ought to know who’s evil right away: “Oh, he’s espousing things with too much force! He’s a servant of evil, all right!”)
Ever think of creating someone who’s stubborn/blind/innocent to the point of frustration, and yet isn’t a traitor? Most ideals can be ridiculous or embarrassing if carried to absurdity. That includes even things usually acclaimed in fantasy novels as universally good and the cherished principles of the heroes, like religious tolerance or sexual freedom. Drop a person who openly practices human sacrifice and hatred of other religions into a religiously tolerant society, and then plant a fanatical priest in there who insists that any abridging of religious freedom is a disaster waiting to happen; the other religions will just have to put up with the chance of their worshippers being snatched. Or drop an STD into a sexually free society, and then invent someone who opposes precautions because it’s less natural, or against the will of the goddess, or whatever.
The most frustrating person is the one who unintentionally does evil in the service of good. Want to rile your readers? Someone like that will do more for the riling than any number of obviously wrong and stupid characters on the opposite side.

5) For POV characters, show the limits of the frustrating characteristics right quick, but don’t let the character recognize them.

This is part of learning to write a POV character so that his or her perceptions, moral and otherwise, are not the limit of the story’s universe. If the audience is free to make up its own mind about the character and his or her position in the world, then readers might well realize that the reaction a naïve character thinks of as, “Oh, she’s just never met anyone like me before” is really the dumbfounded stare of an experienced wanderer realizing, “How can someone as stupid as that survive?”
If a character is stubborn about her religious beliefs, show her preaching and other people displaying emotions that could be interpreted as signs of scorn, contempt, puzzlement or disgust, but which the character thinks of differently. Perhaps she believes that someone who’s silent out of not wanting to argue with her is really pondering what she said. Perhaps she thinks that someone rolling his eyes is responding to what someone else said to her, and not her own words. She may not even realize that there are people in the world not interested in her preaching. The limits of belief can be a wonderful thing for the author, though not so much so for the character who continues along in her little bubble of blindness.
Perhaps the character’s frustrating aspect has nothing to do with beliefs, but rather actions. She might think that dashing at an enemy and endangering the life of a comrade already fighting it is just what good warriors do for one another. Let her take a few wounds, or get the comrade wounded. Put her in ambiguous situations where she survives, but might easily not have. This can start the audience wondering how much courage is a good thing.
It’s a fine line to walk. Do it too well, and the audience might sympathize with the character to the point of finding her epiphany contrived, or might hate her to the point of putting the book down. Think of it as writing a double-edged character flaw, like a too-quick temper. If the tendency is only played as a strength or a flaw, and not both, the character can seem too perfect or too childish. In between is the line you want to find.

6) Let the comeuppance come naturally.

Rather than insisting that the frustrating character break down and adopt the “right” position, or get consumed by the consequences of her frustrating trait, out of the blue, let the comeuppance come from the story itself. Say the naïve character tries to make friends with a dangerous beast. Rather than have the beast bite off her hand or something, say you let her tame it for a little while and go about with it. But she notices that its behavior is still wild, and then it runs away during a crucial moment when she could have used its help, and doesn’t return the love she gave it. That might be the way to break through her barriers and make her realize the world isn’t all pink fluffy bunnies.
Let’s take a character who’s quick-tempered and insolent all the time, and simply will not shut up in front of the bad guy. The Dark Lord can’t kill her because of her place in the plot, or because it would feel contrived. Threats don’t work on her. So he just does something to one of her friends the next time she speaks up. If she insults him again, he does it again. Sooner or later, she’s going to notice the correlation between her mouthing off and her friends getting hurt. That might prompt her to keep her mouth shut. It might also prompt her to do some hard thinking in the jail cell.
I did this with a fanatical priestess character, Lusirimonalata, who constantly interrupted the main narrative of the story whenever she felt it was getting too racy. (Since she was assembling the main narrative out of journal entries, this meant she had power over what the reader did and did not get to see). Another character started appearing during her interludes, drugging and harassing her, and adding parts to the book the priestess wouldn’t have chosen to add, while leaving signs to convince her it was her goddess who did the work. Lusirimonalata refused to question this because of her beliefs, and by the time she started, it was too late. I don’t think it would have worked if I’d had the other character actually appear on stage and Lusirimonalata stupidly ignore her.
A comeuppance done like this fits the story better. And done right, it is so much more satisfying.
D&D stereotypes next, I promise.