As if writing protagonists weren't hard enough, some types are innately more difficult to write than others (at least in my opinion). Let's look at a few I've noticed, clarifying what it is that makes them especially challenging, and how we can pull it off without pulling our hair out.
Unlikeable protagonists
This one's obvious. I personally love writing these types of protagonists because they're complicated, interesting, and unpredictable. There's also a pretty wide umbrella of what it means to be unlikeable. Maybe they're morally gray, or maybe they treat people like garbage, manipulate them, take advantage of them, or just plain disrespect them.
No matter the reason, it's plain to see why they're hard to write: the reader may simply hate them too much to read about their story. So how do you get your readers to keep reading? I'm stealing my answer from K.M. Weiland. I read this post years ago, and it's revolutionized the way I've written unlikeable characters.
It could be a person, a cause, or pretty much anything else. They may be annoying, controlling, mean-spirited, or self-centered, but if there's one thing that pulls on their heartstrings--kids, shelter animals, the homeless, or even a parent or younger sibling--then the reader will see that they're not totally heartless after all.
Consider also giving them something that makes them vulnerable. An insecurity that they share with only the reader. They may be tough and heart-hearted on the outside, but all it takes is one thing someone says for their whole self-image or confidence to come undone.
Passive protagonists
If you're familiar with the Three Act structure, you may be familiar with the fact that protagonists, in one way or another, are passive for about half the book. In the first quarter of the book, we are being introduced to the protagonist's "Normal World." After the first quarter mark, they are thrown out of their Normal World and into the unfamiliar territory of the story's conflict. They're getting their bearings. The midpoint is where they stop reacting to the conflict and start fighting it.
However, it's possible to write a protagonist who is naturally passive. He sits around waiting for exciting stuff to happen to him. Maybe he's conflict-averse or is too stubborn to acknowledge his world is changing. He doesn't do anything and he makes no decisions. Maybe the brave sidekick characters come from the wings and take over the story.
He sounds like a pretty boring protagonist, right? He probably will be and you'll be bored writing him, too. You generally want to avoid passive protagonists, but it can be done if you go into the story knowing he's passive and plan on changing it. In other words, it should be a part of his character arc.
Basically, you follow the same rules of storytelling with the added emphasis that he's passive, conflict-averse, and afraid of change. Conflict happens to him. Maybe he's not initially a major player or big decision-maker (because remember: the protagonist should also be the person with the most at stake), but he grows into this person over the course of the book in gradual and believable ways.
The bottom line is this: force him to engage with the conflict not only by giving him a compelling reason to, but because he has no choice.
Oblivious protagonists
By oblivious, I'm not necessarily talking about someone who's dumb (although it could be). I'm talking about a total space cadet. He doesn't pay attention to his surroundings, he misses out on body language or social skills, maybe he lacks some self-awareness, and so on.
I include this type of character on the list because I think they're hard to write as both the protagonist and from a first-person perspective. Side character? No problem. They end up being the goofy comic relief. But think about how hard it is to write an oblivious character that the reader takes seriously.
Let's look at the typical YA female protagonist. We've likely all heard the cliche where she thinks she's hideous but goes on to describe her appearance in terms that connote an obviously attractive person. We roll our eyes at her obliviousness and begin to lose trust in her when this "Plain Jane" is suddenly stuck in a love triangle with the hottest guys in school.
Do high school girls underestimate their beauty? Sure, yeah. Are they unnecessarily critical of their appearance? Of course. But here's the thing though: most girls who are pretty know they're pretty. They see reiterations of their faces on TV or in magazines. They notice the way guys look at them.
A pretty girl describing herself as ugly when she obviously isn't just makes it look like she's fishing for compliments from the reader. She can still be gorgeous and have self-image issues, but it needs to inform the plot and the lens through which she sees the world. She may have too much of her value wrapped up in her image, making her vulnerable to anyone who thinks she looks less than perfect.
Anyway, there are other ways a character can be oblivious (like I mentioned above). They're still a hard sell. The instant I knew I was writing an oblivious protagonist, I knew I would also have to write the book in third person. If he told the story, he'd miss out on too many of the nuances of the people around him. He wouldn't be observant enough or know enough about the world outside his group of friends.
The other cool thing is that I get to take advantage of dramatic irony--for the protagonist and all the characters. For most of the book, the reader knows more than the characters do--perfect for the horror genre.
Virtuous protagonists
I saved the hardest one for last. Virtuous protagonists are driven by their morals and their need to do the right thing. Well, if they always do the right thing, where's the story? You mean Bob doesn't cheat on his wife, beat his children, and murder people in his spare time? You mean Bob wakes up, goes to work, and... comes home and spends time with his family?
Um...
No, you don't have to make Bob a terrible person to write a great story.
You have a couple of options. You could write someone like Katniss Everdeen, who basically makes all the right decisions because she's courageous, selfless, and upright from the beginning. She doesn't change over the course of the story as much as the world around her changes. That's what The Hunger Games is all about.
You could also write the story about a character who thinks they're good, but the events of the book challenge their morality. The minister Arthur Dimmesdale from The Scarlet Letter has a child out of wedlock and keeps it a secret. Jane Eyre (spoiler alert) grapples with her love for a man who is morally questionable--not to mention already married.
In other words, they need to make a mistake. Or they need to be struggling with some sin that threatens to undermine their identity as virtuous. They need to have a brush with the darkness inside them.
What do you think? Which type of protagonist is hardest for you to write?