People and Characters Rarely Do Things Without Reason
When it comes to motivation, resentment is one of the strongest driving forces. Resentment makes for interesting characters and drama. That's why you see resentful characters all the time in stories. A little reflection is all you need to see that resentment is ubiquitous, no matter how large or small.
Take, for example, someone making you angry. You might forgive this person eventually, but until you deal with the issue, you'll probably harbor bitterness toward them. This bitterness can follow you for years, and you will never be completely open with this person until they do something to take away your resentment, such as apologize to you. Let me give a fictional and personal example.
The murder of Bruce Wayne's parents drove him to become Batman. And boy does he hate criminals. He will do anything in his power to rid the world of selfish thieves and manic crooks. Well, almost anything.
Batman knows that the world would be better off without the Joker. With all his power, he could simply snap the Joker's neck and put an end to his madness. But he never does it. Instead he puts the Joker in prison, knowing that he will eventually escape. Batman chooses not to murder, even if it leads to a worse outcome. Despite being outside the law, Batman never resorts to the methods of a criminal because only a low life criminal commits murder. Batman must have something to distinguish himself - something to justify his actions. Otherwise he would see himself as no better than the man who killed his parents.
Batman also hates guns. Hates. Them. Because a gun is a coward's weapon. A liar's weapon. The weapon of his parents' murderer.
In middle school, a friend of mine had a crush on a popular girl. She didn't like him back, but that didn't stop him from pursuing her.
One day during lunch, the girl and a couple of her friends came over to where we sat and told my friend to stop bothering her. Instead of telling him nicely and privately, they stand over him and talk loud enough for everyone to hear. They tell him to stop wasting his time. To give up. That she has never liked him and never will. I will never forget the look on my friend's face as he hung his head in silence while these girls dug their heels into his self esteem.
Looking back, I can see that we were only kids. That these girl have surely changed. That they probably remember and regret how cruel they were to my friend that day. And yet, I still can't bring myself to forgive them. I can't help but feel anger boiling in my stomach whenever I hear one of their names. I dislike anything they enjoy and refuse to become friends with anyone that might remind me of them. One of them is a talented artist? I've seen better. One of them speaks French? That's so pretentious. It's been over 10 years since that day and I still bear an irrational animosity.
We resist what we resent. Compared to motivations like revenge or fame that guide you toward something, resentment guides you away.
Think, for a moment, of things that you refuse to do. They can be major things like murder and rape, or small things like eating meat, doing drugs, and buying a Macbook Pro. When we finally do give into something we've been trying to deny, we can't help but feel guilty. Often it's not the action that disgusts us, but the idea that we are able to become the very thing we hate. If you're teamed up with a person who has wronged you in the past, you will resist and dismiss any of their ideas, no matter how good, simply because of who they are. This is the power of resentment.
In keeping my posts about characters and stories, I'll leave off with an example of a great character driven by resentment.
Magneto
"I am no hero. Merely a man who has seen and done and endured what can never be forgotten or forgiven."
Magneto's experiences surviving the Holocaust shaped his outlook on the situation that mutants face in the world. When the government begins to limit the freedoms of mutants, he can't help but see the parallel to Jews in Nazi Germany.
Magneto resents the systematic oppression of minorities. He is willing to use deadly force to protect his own kind. Despite his extreme measures, he is clearly not selfish. Every one of his plans are for the purpose of creating a better world of his fellow mutants. He has seen what can happen when you yield an inch to your oppressors, and will never open himself up to the possibility again. He is determined to keep such atrocities from ever being committed against mutants.
And this is just how powerful resentment can be, sometimes overshadowing positive motivators like money, health, or even happiness. While bitterness can drive a you forward, too much of it will consume you. Filling yourself with only rage, hate, cynicism will still make you empty.