
Recently he lectured us on how important it was NEVER to mark students' papers with Red Pens, because the Red Pen would discourage them and suggest to them that their work was something that others could deface. Instead, we were to write them all individual letters, commenting not on what is right and wrong, but instead giving gentle guidance on how a student's choices in the assignment reflect their thought processes.
I’m teaching a total of 150 students, and I only have one worthless TA. I objected: individual letters to 150 students? He looked at the rest of the group, sighed, and said "You'll find, as your career unfolds, that you can always find excuses for not doing your best by your students."