Posture, Proficiency, Performance. These elements I've used in my teacher for over 30 years.
Knowing how an instrument fits you gives you the balance to play without unnecessary tension. Learning the techniques gives you confidence. Sharing your music making is the joy and the performance. Balancing technique and feeling is a classical approach in many genres of music be it played on a tin whistle, tuba, ukulele or guitar. I have used this approach in my teaching and see students achieve their goals.