I'm probably halfway through my career and still feel like a perpetual beginner because of this syndrome. It has brought me many material and intellectual pleas

I'm probably halfway through my career and still feel like a perpetual beginner because of this syndrome. It has brought me many material and intellectual pleasures and tangible benefits, including a decent living; but I increasingly feel like if I want to progress in my career, it's time to specialize a great deal in a tiny subset of my interests. There's real power in being able to say No to things, and real wisdom in knowing what to say No to. I fear I lack both of these! It's vexing in the extreme.