It seems to me regret is wishing we had done something differently based on information we didn’t have at the time.

My son once ate 3 homemade buttermilk biscuits in rapid succession.  When I asked them how they tasted, he responded inaudibly.  When I asked again he muttered something I couldn’t understand.  On the third ask he said very clearly, “Regret. They taste like regret.”

Though a humorous example, he was basing his choice on the information he had at that moment (how full he was, how tasty the biscuits were, how many were left, how they might not taste as good tomorrow).  Once the choice was made, the deed done, he received new information which, by then, could not be used in the decision making process.  It reminds me of the definition of insanity, ‘doing the same thing and expecting different results.’

I imagine we all walk around with regrets…some big, some small.  But the feeling changes nothing.  The choice was already made.  We are trying to apply this moment’s knowledge to a previous moment.  Until time travel is possible, I don’t see that happening.  I imagine we would be better served trying to use the feeling to act in a way to right the regretted.  Or, we can embrace the emotional discomfort that often comes along with learning something and thereby, hopefully, avoid a future regret.