discipline
It's a slogan that, to get anywhere in music, you have to have discipline. It's true, but I think we tend to confuse it with an almost military attitude. Discipline doesn’t have to mean being severe.
Discipline is the line that can’t be crossed between a teacher and student - it’s what makes the relationship professional. Discipline asks a student to do what’s asked, and it asks a teacher to be conscientious of their student.
But right up until we cross this line, we should be as friendly and easygoing as possible. We learn best with a light touch.