From The Interaction of Color by Albers - a book I was not that thrilled with (probably due to it being the 1972 condensed edition which has few color plates to refer to), but in which I did enjoy this quote:

"In the end, teaching is a matter not of method but of heart. Therefore, the most decisive factor is the teacher's personality. His enthusiastic concern with the student's growth counts more than how much he knows. It is well known that "the teacher is always right," but rarely does this fact elicit respect or sympathy; even less often does it prove competence and authority.

But the teacher actually is right and always will gain confidence when he admits that he does not know, that he cannot decide, and as is often is with color, that he is unable to make a choice or to give advice.

Besides, good teaching is more a giving of right questions than a giving of right answers."