Woulda, coulda, shoulda! How much time do you spend thinking about the past and things that you should have done differently, or could have done better, or given the chance, wouldn’t even do at all? Unless you are rehearsing it in your mind so that you do not make the same mistake again, I would counter, this is not the best use of your brain power and energy for time spent. There is not a very good return on investment.
Time and brain resources better spent would be focusing on future potentials, opportunities, and dreams where you can have an impact. The world is wet cement! Focus on leaving a footprint for the future vs. stewing over the muddy tracks of the past!