Among my students is an extraordinarily sensitive world-renowned scientist. She was trained according to the British system in Australia, where she grew up. She came to me as an adult wanting, as she put it, to know "where the music part was."
She could recognize it when she heard it but felt entirely removed from it when playing, even though the repertoire she played would be considered quite accomplished -- Mendelssohn Songs Without Words, for example.
The music part is not so easy to define, but in her case it definitely had to do with the fact that the printed page had absolutely nothing to do with listening. It was strictly a matter of a diagram a la Fred Astaire Dancing School: "put this foot here and that foot there" and you are somehow magically going to be dancing.
Well, it doesn't work that way. To this day she has great difficulty imagining sounds as she reads. The disconnect between her fingers and her ear is typical of people whose attention is never drawn to the primacy of the ear in reading / playing the piano.
There are so many people like her : in fact, I would count myself among them, until a discerning teacher required me to change my ways. It took a year of extremely painful reco-ordination, painful in that I had to view as separate activities moving my fingers from aiming for right notes, in other words, I had to break down all the elements of reading so that I could put them back together in the proper order. Imagine how difficult it was to play wrong notes on purpose after years of being led to believe that that was streng verboten (strictly prohibited).
I am going to start an Institute for Subjective Listening next year. If you have trouble reading music or teaching anyone to read, or if you have ever been bored while practicing or teaching, you will be a candidate. Stay tuned.