Regret is useful only for considering how you might better handle the same situation, were it to arise again in the future. Regret uses the past to energize negativity into the present and extend the suffering long after the event is over. You could not have acted differently considering the confluence of internal programming that coalesced to cause your behavior at the time. Regret signals you’ve learned a lesson. The self-loving thing to do is forgive yourself for acting in a way that you now see was less-than-perfect and make amends, if necessary. Then…
Let it go.
Steve and Jarl