I feel the same way. Every single time I place a ton of importance on something, whether it's a relationship, or a project/career, it always comes back to bite me when I realize I can't have it all, and don't have 100% control of circumstances in my life.

To me, living life and always wondering whether I'm making the most of it every step along the way takes the fun out of it. Of course some introspection is good, of course, but I don't like to take life so seriously.