At least, that's the conclusion of a recent study out of Florida State University, where researchers examined the complex dynamics of why some relationships last, and others fail.

The findings run counter to the recent trend of "positive psychology" in which couples are taught that forgiveness, optimism, kindness and positive thinking can help heal a broken relationship following a serious transgression, admits lead researcher James McNulty.

But in his research, McNulty found that sometimes the "short-term discomfort of an angry but honest conversation" can be beneficial to the relationship in the long run.

This is particularly true among "disagreeable" spouses who may take advantage of their partner's good nature and willingness to forgive and forget.

"Believing a partner is forgiving leads agreeable people to be less likely to offend that partner and disagreeable people to be more likely to offend that partner," he said in a statement.

Moreover, expressing anger can serve as an important role in signaling that the offending behavior is unacceptable, he added.

"This work suggests people need to be flexible in how they address the problems that will inevitably arise over the course of their relationships. There is no 'magic bullet,' no single way to think or behave in a relationship. The consequences of each decision we make in our relationships depends on the circumstances that surround that decision."

The research was presented at the American Psychological Association in Orlando earlier this month.