Learning to play what you feel does not require extensive knowledge of harmony or theory. All that is required is the ability to do two things:
1. Believe that you know enough
2. Believe that you're good enough
Thousands of classically trained pianists are able to play Rachmaninoff and Bach but are unable to express themselves poetically at the keyboard. Why? Because of the above 2 beliefs! It's not enough to have mastered piano technique.
For example, many would be writers understand how to construct a compelling plot and know how a story should be written, but until they have freed their inner voice from criticism...until they believe that they are good enough to write that story, it simply won't get done!
The same goes for music and any other art. I can't tell you how many times I repeated the above 2 statements to myself because I really wanted to get past my fear of being able to create music at the piano. I wanted to play what I felt at any given time - to be able to improvise. But this was nearly impossible as long as there was some voice in me that said I just wasn't good enough. And believe me, we ALL have these voices somewhere in our heads at one time or another.
Eventually, I got past the need to seek other's approval and realized that I was more important than the music. I learned that I already knew more than enough to play the piano. I also came to believe I was good enough and that no one person will every know it all or be a "perfect" player.
