Your partner cheats. Your coworker takes credit for all the work on a joint project. Naturally, what you want is sweet, sweet revenge.

This instinct is indeed natural, programmed into humans who feel threatened. Humans are protective beings, Dr. Robin Gaines Lanzi, professor of health behavior at the University of Alabama at Birmingham, explained to the New York Times: We're motivated to seek revenge — to harm someone who has harmed you — when we feel attacked, mistreated, betrayed, or rejected.

"If what we care about — whether it's our children, spouse or other loved ones, our work or some cause that we are passionate about — is harmed or threatened in any way, it is instinctual to want to do something about it," said Gaines Lanzi.

According to evolutionary psychologists, a world without laws and prisons was kept in check by revenge, and our earliest ancestors relied on fear of retaliation to keep the peace and serve justice.

"Acts of revenge not only sought to deter a second harmful act by a wrongdoer but also acted as an insurance policy against future harm by others, a warning signal that you're someone who will not tolerate mistreatment," Michael McCullough, a professor of psychology at the University of Miami, told the Washington Post.

They also feel good. In a recent psychological experiment, researchers asked college students to write a short essay on which they would receive comments. The essays were randomly assigned to receive either positive feedback ("great essay!") or negative ones ("one of the worst essays that I have EVER read!"). Afterward, participants' emotional states were assessed, and subjects were offered the chance to retaliate by sticking pins into a voodoo doll that represented the person who critiqued their essay. Those who had received negative comments had a slump in mood after reading their feedback, but attacking the voodoo doll put their moods back on par with those who had received positive comments.

"In novels and movies, revenge turns out to be this great cleansing moment that permits someone who's been abused to triumph," Peg Streep, a science writer and author of "Mean Mothers: Overcoming the Legacy of Hurt," told the New York Times.

"Revenge works well in plot lines because there's something very satisfying about a tit-for-tat payback, especially in a world that isn't always fair," she said.

And it's not just in the movies. But the sweet taste of revenge doesn't linger. According to research reported in the Washington Post, the positive feelings after revenge are fleeting, spiking in the moment, and then diminishing five, ten, and 45 minutes later—until respondents report feeling worse than they did before they sought revenge.

We may be hardwired for revenge, but is it healthy?

"Oftentimes it's not necessarily the emotion itself that's bad or toxic, but how one copes with it," Dr. Erin Engle, clinical director of Psychiatry Specialty Services at Columbia University Medical Center, told the New York Times. On Khloe Kardashian's reality show, Revenge Body, a wronged party undergoes a transformative makeover, usually including weight loss, designed to make their ex eat their heart out. But obsessive rumination that dwells on the past doesn't help an individual develop, grow and move forward.

On the other hand, if the wronged party can take a future-oriented approach, she said, "that kind of thinking tends to orient the person to the future and can make them stronger, happier and healthier."

When the desire to seek revenge arises, it can be helpful to look at the feelings inspiring it. The uncomfortable feelings from a betrayal or wrongdoing can be deeply illuminating about our values and the way we want to live.

When it comes to meaningful relationships, research suggests "what the angry mind ultimately wants is a change of heart from the transgressor," McCullough said. Studies show that when a victim receives an explanation and an apology, the desire for revenge weakens.

"Revenge may make you feel better for a moment," McCullough adds, "but making the effort to repair a valuable relationship can pay bigger dividends over a lifetime."

"If you focus your attention on getting yourself emotionally, mentally and physically healthier," Tiffany Towers, a clinical and forensic psychologist told the New York Times, "not only will you feel better, but you will be able to handle future difficulties with more grace and wisdom."

And that is truly the sweetest revenge of all.