He wanted you to get things right the first time. He'd mention that Paxton would say that 'It's the preparation that's everything. Painting the figure came later in a student's career, and sometimes gave way entirely to drawing. Lack noted that he spent most of his last two years with Gammell studying shapes, doing pencil drawing. It's the preparation that's everything.
Any idiot can go back and put a pretty line over it.
He felt that one of the reasons the Boston School had fallen apart was that people were doing just painting and nothing else. The idea of putting the right note in the right place and the drawing will take care of itself-well, it works in theory, not in fact. I had never heard of it before - none of us had ever heard of it before. It was most enlightening and most enabling. It was the single most important thing.