The shortest answer to this question would be – We regret because we can’t forgive ourselves. We can’t forgive ourselves for behaving a certain way, making certain decisions, hurting someone, not taking action, not spending enough time doing something we love or being with someone we love. Simply put, regret is basically self-blame. Looking back at what was and concluding that we could have done something differently, we could have been different, we could have lived differently, spend our time wisely.
When we get wiser and look at things at retrospect, we get stuck on disapproving our past and feeling bad about it. Why? Because we place our current wiser self in the past. The current-self is wiser than the past-self and has opinions about the consequences of past-self actions or the lack of those actions. But the current self is not always wise enough to observe itself and see that by placing itself in the past using the imagination he is objecting to what has already happened, blaming the old self for not foreseeing what is about to happen. Objecting the old-self and the entire learning experience that allowed the old-self to evolve to the current-self.
Evolving and learning, this is what life is all about. Learning to be compassionate toward yourself, noticing your current-self blaming the old-self and realizing that there is absolutely no point in doing that. Also, the current-self should not be blamed for blaming the old-self. Blaming yourself stops the evolution of your heart, stops you from embracing yourself as you were and as you are right now. You should stop regretting and blaming yourself not because you need to or it is the right thing to do, but because you truly believe that none of the things that you disapprove of or dislike are your fault.
Some of us hold tightly to a belief that our current life is a direct consequence of our actions, and this is somewhat true as long as you believe that you should take full responsibility for your past actions.
But who’s actions were they? Past actions are the result of the past decisions of your past-self about your past experiences and circumstances. That happened. You have learned and evolved since then. Now you’re sitting and contemplating about what could have happened if you were then as you are now?
It is time to forgive your old-self for not being able to foresee the consequences and predict the future because no one can do that. It is time to see that you did your best. Each passing moment of your life you did your best considering the circumstances of who you were and what you felt. It is time to stop blaming yourself for blaming yourself. It is time.