Hey Cygnus, I have a perfect 20-20 hindsight also! I can look back and see how things could have been different "if only..."
Trouble is, if I hadn't made those mistakes or errors, I would not have gained the wisdom I have now.
The challenge for me is how to put the wisdom I have gained into practice later in life.
I read a book that helped
CALLINGS by Gregg Levoy

It shows what people went through and how they reinvented themselves later in life using the transferable skill sets they learned earlier in life.