Me and my shadow

I don't know if it's just part of being human, or of being thirtysomething, or simply being me, but introspection seems to take up a lot of emotional energy. I seem to be forever self-examining and self-critiqueing. If this sounds a bit familiar to you too then you'll know that the tendency is not to dwell on your good points but your bad points. Why is that the default setting? I was just considering this and began thinking of it as a fascination, or even an obsession, with my own shadow. How weird would that be? But then I thought - shadows get bigger the further you are from the source of light. Maybe if I could concentrate on getting myself closer to that light I wouldn't have as much shadow to explore.