I’m almost convinced that you, same in my case, have read many books about personal development with great interest and curiosity. Self-help materials, maybe psychology books written by big names in the field and it’s wonderful to be self-taught. And yes, new horizons open through introspection and discovering amazing and charming ways (sometimes even seductive) to understand a human being. Still, it’s a threshold that you cannot pass and you cannot go much further in the dialogue with yourself!
To answer your question, coaching changed the way I think over a personal situation, through direct questions and challenges placed by the coach, by the fact that a coach challenged me to dispute some of my irrational beliefs about myself and has looked at me like the man that has the necessary resources to fulfilling their personal desires. And from coachee, I became a coach. Because I wanted that.
I managed through coaching (I was the client of a coach many times), to gain clarity in thinking, concrete action steps, determination and motivation. I understood that in order to change, the challenge lies in myself and I’m the one responsible to observe myself, to actively dispute my thinking style, to keep feeling and to learn new ways to reflect and understand. That’s the magic of coaching!