So many people these days are selling us pithy platitudes on why we shouldn’t feel anger or why we shouldn’t feel regret. Even the Dalai Lama seems to paint anger in a negative light. This is tragically misguided.
Anger and regret are both healthy and ‘useful’ emotions (I hesitate to use the term ‘useful’ there, because emotions are not mere things to be manipulated, they’re more intimate than that). To quote one of Neale Donald Walsch’s books, “Expressed with love, anger is the discharge of disharmony, not the creator of it.” A book of his also says anger is ‘the tool you have which allows you to say, “No, thank you.”‘
The problem is that anger is often expressed harshly, searingly, without much restraint or refinement. To quote Neale’s book, “Anger that is not wonderfully expressed, but expressed through verbal or physical violence, does not heal, but inflicts injury.”
Since the most common way in which people express anger is to do it with the intent to damage the other, people tend to think of anger as being inherently an unvirtuous thing to be avoided or overcome. But anger is actually one of the five natural emotions that serve us, having legitimate purposes.
Anger also has the unfortunate association with hatred, which is a vile emotion and should be avoided. Anger is not hatred, however. I would say that hatred is a distortion of love that arises when one is not able to adequately express strong feelings of anger toward another.
I always think of the quintessential example of expressing anger with gravity but without malice as the part on The Lord of the Rings: The Fellowship of the Ring where Gandalf says to Bilbo, “I am not trying to rob you!” Here’s a link to it: https://youtu.be/4Yy0pPTrHlk?t=120
Regret (not to be confused with guilt—more on that later), to paraphrase one of Neale’s books, is the feeling that tells you that you do not want to do a thing again. People who advocate having “no regrets” are effectively advocating sociopathy. Everyone who’s human does something at some point that they shouldn’t have (or, to put it more accurately, that does not reflect who they really want to be) that harms someone else, and it’s impertinent to pretend otherwise or to avoid feeling the repercussions of this.
Some may reason that it’s unnecessary to feel regret because one can simply choose not to do something again they did wrong instead. But I think this line of reasoning may arise from the false assumption that regret is inherently a negative thing. As with the case of anger, people assume that regret is wholly negative because, on the surface, its effects are uncomfortable.
So why should we feel regret if we can simply choose not to do a thing again? Because not all of our behavior is or should be calculated; a lot of it arises from our emotional system. We are emotional beings, and acting from emotions is healthy. If we do not feel the emotion of regret, perhaps we won’t properly integrate the update to our behavior. Maybe we’ll forget later when it comes time to heed the results of the previous time we did something. Or maybe we’ll sometimes act rashly or purely out of emotion without the proper mental check being put on our actions. Or maybe we’ll fail to properly generalize the bad thing we did and regard new situations as irrelevant to that thing when they really aren’t. And learning something on an emotional level rather than just remembering it should certainly carry over better to future lives, if you believe in that sorta thing.
Guilt, however, is not regret. Guilt is essentially self-punishment, or internalization of others’ condemnation. When we feel guilt, we deny ourselves necessary spiritual nourishment or sort of ‘hold ourselves down’ for the sake of some kind of atonement, and that doesn’t help anybody. I believe in one of Neale’s books it says that with guilt, we will only wither and die, and also that guilt and fear are the only enemies of man.
(“But we need fear to stop us from doing something stupid that gets us harmed or killed,” you say. No, I’d say, fear isn’t necessary for this; caution is.)
I wrote more about guilt here [https://www.quora.com/Should-Christians-feel-guilty-if-they-experience-constant-lustful-thoughts/answer/Richard-A-Nichols-III] and here [https://www.quora.com/Should-you-feel-guilty-when-you-decline-to-give-a-dollar-to-a-homeless-person-asking-for-money/answer/Richard-A-Nichols-III].
More on what Neale’s books have to say about anger and the five natural emotions can be seen here [https://meaningfulponderings.wordpress.com/2012/12/30/anger-is-a-healer-from-the-new-revelations-by-neale-donald-walsch/] and here [http://spiritlibrary.com/neale-donald-walsch/five-natural-emotions].