I told a physician (long-term clinical relationship, but not primary-care MD) once, “I’ve never looked back”. He replied, “Don’t start now!” I didn’t mean that I don’t look for lessons from the past… of course, I do, and my interlocutor knew what I meant. Regrets are for putzes… you did what you did and it had certain consequences, and you can’t do a thing of it. You can, obviously, draw wisdom from it and you can also try to made amends if you did wrong or if an error of yours caused someone pain or hurt. Repentance and forgiveness for the past are real articles… they aren’t hollow exercises. However, regrets for what’s done and over are for the weak and immature. You did it, you own it, and that’s that.
The past is immutable and gone… the future is “not yet” and we don’t possess it yet… we live in the present, and we CAN do something about that…