In the "regret puzzle", one lives their life with "what if" thinking. What if I had not made this bad choice or that bad choice? Presume that you know it was a bad choice and also presume that you could go back in time and change that choice to a better choice. If it is a decision or choice of any importance, it will likely chance the trajectory of your life is some way. In other words, it would change the possible decisions you make in the future and/or the outcome thereof. Now imagine each decision you make/outcome 'you choose' is a puzzle piece. If you change the shape of that puzzle piece, it will necessarily effect the puzzle pieces--decisions/choices/outcomes--surrounding it. One has no way of knowing how a decision today will alter a decision/outcome tomorrow. Typically, we assume those surrounding decisions/outcomes will be either unaffected or better, but there is no way of knowing for sure. Hence, while it is proper to mourn bad choices or decisions, it is doubly pointless to live with regret and 'what if' thinking surrounding them. Not only can we not go back and 'fix' mistakes in the past, we don't even know how it would affect surrounding choices/decisions/outcomes.
Seeing this has helped me not to live in my poor choices/mistakes.
