The purpose of guilty feelings is to alert you when you've done or are about to do something that might cause harm or distress to another person. You can then avoid the action in question or make up for your wrongdoing with apologies or gestures of atonement. As such, guilt serves an important role in helping us maintain and preserve our most valuable relationships.
While guilt is useful in smaller doses, it is anything but in larger ones. Excessive or unresolved guilt is in essence a form of "psychological injury" because it impacts psychological functioning. Specifically, guilty feelings are preoccupying and distracting, they impair focus and concentration (e.g., being productive at work will be a struggle if you just realized you forgot your spouse's birthday), and they prevent you from enjoying life and experiencing the full range of happiness you could and should.
But that is not the whole story. Recent studies demonstrate that guilt is more of a trickster than we realized. Guilt influences our unconscious as well as our conscious minds. The ways in which it does so are quite surprising:
1. Feeling guilty can make you feel physically heavier and more labored.
Researchers divided participants into two groups. One was asked to recall a time they acted unethically (the guilt group) and the other, a time they acted ethically (the control group). They then asked both groups to estimate their current weight compared to their "usual" weight. Guilty participants estimated their current weight compared to their normal weight as significantly greater than those in the ethical memory group. They also estimated the effort required for them to do certain tasks as much greater than non-guilty participants (indicating that guilt made them feel more labored as well).
2. Feeling weighed down can make you more vulnerable to guilt.
The relationship between guilt and subjective weight runs both ways. Guilty feelings can make you feel heavier, but being physically weighed down also makes you more vulnerable to guilt. Participants were given either heavy or light backpacks and put through a manipulation to induce guilty feelings. Participants wearing heavy backpacks were significantly more likely to feel guilty than those wearing light backpacks.
3. Feeling guilty can make you self-punish.
In this series of studies, researchers made participants feel guilty for depriving a fellow participant (who was actually a research confederate) of a few lottery tickets. Guilty participants were willing to resort to giving themselves mild electrical shocks to atone for their guilt, especially when they found themselves in the presence of their "deprived" (and fake) fellow participant. Researchers found such strong evidence for this self-punishment-as-atonement-for-guilt phenomenon they gave it a name -- the Dobby Effect (named for the self-punishing elf in the Harry Potter books).
4. Guilt tripping your partner can backfire.
Guilt trips are a form of verbal or nonverbal communication in which a guilt inducer tries to induce guilty feelings in someone in an effort to control their behavior. As such, guilt trips are a form of psychological manipulation and coercion. Scientists found that when people responded to criticism from their partner with exaggerated expressions of hurt (in other words, by giving them a guilt trip), their partners responded by reassuring them. However, the reassurance came with a price. Their partners also reported feeling less satisfied in the relationship as a result.
5. Partial confessions aren't worth it.
In another series of studies, researchers found that people who cheat might favor making partial confessions, as doing so allows them to relieve their guilt without admitting full responsibility. They also assume (correctly) that a partial confession will be more believable than none. However, it turns out partial confessions come with a price. People ended up feeling worse emotionally after a partial confession than those who did not confess at all or those who confessed fully. They felt more guilt about their actions than those who confessed fully, and they felt more regret about confessing as well.
The best way to manage guilty feelings is to address them as soon as possible by treating the emotional wounds they create. But try not to feel guilty if you don't.