I feel very fortunate that I have difficulty with a great many things having to do with music, because the fact that I have to face my difficulties every day makes me a better teacher. The instrumental teachers who have really helped me have all been people who worked all the time to improve their own playing. Teachers who have tried to show me how "easy" it is to do something on their instrument, using spoken phrases like "play it smoothly" or "play it like you are in a grand cathedral" have never given me anything I couldn't give myself. As far as I'm concerned, phrases like that are meaningless when it comes to directing the thousands of neural transmitters and hundreds of muscles in the hands and arms to do what an accomplished player would call a simple maneuver. Students need to be told exactly how to accomplish a task, and they need to have the task broken down into steps that can be followed. The only way I learn, even from myself (I am my own teacher now), is by breaking down tasks and identifying and separating the difficulties.
Drawing the bow in a straight line, for example, is simple in concept, but it is probably one of the most difficult things for a string player to do, especially in circumstances that involve difficult left hand manipulations and odd harmonic situations. It is a perennial difficulty for me, something I always have to work on improving. Because I have this difficulty I can notice it in my students and help them improve their bow arms (which improves everything else). If I didn't have this, as well as a whole slew of other "challenges," I believe that the development of my students would suffer. If everything came easily to me, I don't think I would be much of a teacher. If I didn't have to work for what I have accomplished and for what I will accomplish, I don't think that I would ever feel satisfied as a musician.