Whether it be coaching or teaching, it's a decision to teach others something we love. Unless someone is desperate for a pay check, they won't want to deal with the hassle of learning the material and teaching to people. Having a field filled with people who are passionate about their subject is a good thing. The problem is the teacher needs to relate the material to their students in a way that interests them and they understand.

Albert Einstein said it best, “If you can't explain it to a sixth grader, than you don't understand it yourself.” It's not about you and what you are interested in, it's about your athletes. You could literally know everything there is to know about shot put, but if you can't teach it to someone in a way they understand they will not think of you as a good coach.

Don't expect your athletes or students to share your special interest in your field.