What is Missing: What is that list of things you have always wanted to try/do/experience...
A commitment to your self to do one of them this week/weekend. It doesn't have to be big (jump out of an airplane) just something (make a model out of clay or plant an herb garden).
These things that you want to try are holding you back from a stronger sense of self. Work at accomplishing these and you will notice a stronger belief in yourself.
Book to check out: "You Can Do It!"
