Spinoza on the Futility of Remorse, Guilt, Shame, and Repentance.
While we believe we are free agents with free will so we will buy into remorse etc. Dropping our addiction to the idea we are free has the strange effect of freeing us from destructive emotions.
Repentance is pain accompanied by the idea of some deed which we believe we have done from free decision of the mind. The Ethics, Spinoza
You might be surprised to know that many people are afflicted with regrets, guilt, shame, and the need to repent of previous actions. These are curses on the human race and make a hefty contribution to the misery in the world. The ease with which we can be manipulated through these emotions is well known to those in power in society and religion. The Christian religion is particularly smitten with these destructive emotions, with one of its central messages being that we are ruined at birth and should spend the rest of our lives repenting for our fallen state. It's a truly miserable life that is driven by such sentiments, but it has proved to be a very strong mechanism for control. A negative view of sex is almost ubiquitous in the Roman Catholic Church and is perhaps the best lever to create shame, guilt, and the rest. And perhaps not by accident, it is also the most powerful of the world's religious establishments.
Now Spinoza makes a very good point on these damning emotions. They are in fact useful as a means of regulating societal behavior. Shame for example is the dread that others will come to learn of behavior that would be roundly disapproved of. If there was no disapproval, there would be no sense of shame. And so we still see the quite legitimate shaming of people involved in sexual abuse. But Spinoza is speaking of individuals who have no sense of what is right and wrong from the perspective of what makes society work and what brings chaos and destruction. For the person able to operate from their own reason then the emotions of shame, repentance, and so on are wholly futile, achieving nothing and causing misery.
In the quote above it is worth noting that Spinoza highlights one of the contributing causes to these emotions, and specifically repentance. It is because "... we believe we have done (a thing) from the free decision of the mind." I've already produced a short piece on the illusion of free will. If there is no free will then there cannot be any praise or blame. We do what we do because we were never going to do anything else. To reflect on the past and believe we could have done differently is nothing more than imagination, and destructive imagination at that. In any case, a strange understanding that comes from the zen tradition says "every decision you make will be a mistake."
This whole array of emotions that feed on regret for past actions is such a bane that Spinoza considered them to be one of two curses upon the human race.
The two archenemies of the human race: Hatred, and Remorse. - Spinoza
It isn't so easy to drop these destructive emotions, but it certainly helps to understand that we are not free agents when dealing with them.