Do you ever reflect back on your life and land on things you did or decisions you made which you now question?

I have and I do, but, of course, in the absence of a Time Machine, we can not reverse history and who knows, if we could, if it would even make a difference.  

What I do know is that such background and experience is invaluable in leading one's life going forward.  

It is also valuable in advising others and one piece of such advice is that, just as one does not get a second chance to make a good first impression, there are no do overs in life!