Hi, great post.
I found the solution (at least until now) in making a single big decision:
When I was doing the research for my phd I found my personal low-point. A colleague told me there would be two types of personalities. Beginners who are starting over and over again without finishing a single thing and finishers who never quit. I chose to be a finisher and never changed on that. It has always kept me up.
If i get the message right, what you mean is those who don't complete projects they start or leave them halfway are those who suffer a lot from depression right?