You hear a lot of talk about how to let go of grudges — how to forgive and forget using a psychological technique or a spiritual process.

And I get it; I've been actively working on letting go of those frustrations in life that are ultimately unimportant or out of my control.

But sometimes holding on is healthy, too. Or so says Sophie Hannah, author of a new book on the subject called "How to Hold a Grudge." (It's important to note that Hannah isn't a psychologist — she's a novelist who came to these conclusions as part of her own therapy process.)

How can we make a grudge work for us? In these four ways.

1. Grudges can empower you

Hannah says a grudge isn't just a feeling like anger or frustration. It's the story you tell yourself about a given situation. If you are treated poorly by a family member or coworker, the grudge is the story you put together about what happened to you.

In this way, a grudge takes a negative emotion and turns it into a narrative that you control, which is empowering.

Hannah suggests writing your grudge out and putting that document somewhere you can come back to it. You and/or the feelings you have about the situation might change. This isn't about holding all grudges — just some of them, for good reason.

2. Grudges can help you reflect

In the process of telling our grudge story, we can better understand our part in it and what we might have done wrong. Or — and this is important —understand why what someone else did to us was wrong. If we feel badly following, say, a fight with a friend, it's worth examining why.

You might come to the conclusion that you said something unkind, in which case, you should apologize. But if the other person is the one in the wrong, understanding why what they said was hurtful matters.

Analyze your role in the situation after it has passed. Then come back to it days or weeks later. Your feelings might change once you look at it in hindsight, and then the grudge can pass naturally. In this way, accepting and holding onto a grudge can actually help you let it go when appropriate.

3. Grudges can help you understand negative feelings

Negative feelings can signal that you feel hurt because someone was trying to hurt you. They don't necessarily mean there's something wrong with your reaction. Figuring that out is part of your grudge story.

"When there's some kind of suboptimal thing that somebody has done to us, the grudge is our story that we remember about that incident, because it benefits you to have that story remembered," Hannah told The New York Times.

4. Grudges can help you set limits

"Grudges can be a good thing," co-host Sunny Hostin points out in "The View" video above. "Because people will do what you allow them to do to you, and so with a grudge, you remember what people have done to you so they don't do it to you again."

Grudges can help you set limits with what kind of behavior you will accept from other people. "I remember everything that everybody does to me, and then I hold it up in my head," says Hostin.

If you let everything that upsets you go, it can lead to people taking advantage of you.

"We're constantly getting messages that our mistreatment doesn't matter," Hannah told the N.Y. Times. And of course, mistreatment does matter. Sometimes we need to let it go. But holding a grudge is a way to draw a line in the sand and remind yourself that when someone steps over that line, it's unacceptable to you.

While I'm still working on letting go, I'm also being mindful that some grudges are worth keeping.

Starre Vartan ( @ecochickie ) covers conscious consumption, health and science as she travels the world exploring new cultures and ideas.

Holding a grudge can be surprisingly healthy
Here are 4 ways holding a grudge can be good for you, from self-reflection to setting limits.