The quickest way to write a dull story is to make your hero always good. This creates a flat, one-dimensional character and quickly bores your audience. To round out your hero, make him or her the bad guy temporarily.
If you study great movies, all heroes wind up playing the role of the bad guy, often inadvertently. In “Thelma and Louise,” the police are convinced the two women are cop killers and hardened criminals even though one police detective truly believes they were the victim of circumstances.
In “Tootsie,” the hero disguises himself as a woman and befriends his co-star that he’s in love with. When his co-star says she’d like a man to be honest and say he wants to take her to bed, the hero meets her at party as a man (so she doesn’t recognize him) and promptly asks her to bed. Surprisingly, his co-star immediately slaps him and leaves, making the hero look like the male chauvinist bad guy in the scene.
In “Star Wars,” Luke disguises himself as a stormtrooper and pretends to lead Chewbacca off in handcuffs so they can get to Princess Leia’s prison cell. In “Die Hard,” John McClane is mistaken by the FBI for a terrorist and is shot at.
The purpose of making the hero the bad guy is to let the hero (and the audience) see another side of the hero. Sometimes the hero plays a bad guy just to hide in plain sight like in “Star Wars.” Other times the hero plays a bad guy to let the hero (and the audience) learn something from the event.
In “Brittany Runs a Marathon,” an overweight woman named Brittany starts running to achieve her ultimate goal of running and completing the New York City marathon. Because she’s been overweight for so long, she doesn’t like the fact that men and woman treat her differently than if she were skinny.
As she loses weight, she starts feeling better about herself but when her life starts falling apart, she starts gaining the weight back on again. That’s when she attends a party and sees an overweight woman happily married to a much thinner man. Now Brittany is drunk and angry at the state of her own life so she lashes out at the overweight woman, telling her that people look at her and her husband differently because she’s fat. Essentially, Brittany is projecting her own fears and anger on to an innocent woman, but this helps reveal Brittany’s own feelings about past injustice by becoming the type of person she hates in others.
By making the hero the bad guy temporarily, he or she can literally become the villain who’s tormenting them. This can be a powerful emotional moment that makes the hero vulnerable and real while also more sympathetic at the same time.
If you fail to make your hero the bad guy temporarily, you risk creating a hero who’s so good and perfect that he or she is just plain boring. By making your hero a bad guy momentarily, you make your hero more like a real person and turn your story into one that’s more interesting and believable.