Dear College Student......
From the Forbes article "Dear Student: I Don't Lie Awake At Night Thinking of Ways to Ruin Your Life," by economics professor Art Carden:
"First, I do not “take off” points. You earn them. The difference is not merely rhetorical, nor is it trivial. In other words, you start with zero points and earn your way to a grade.
Second, this means that the burden of proof is on you to demonstrate that you have mastered the material. It is not on me to demonstrate that you have not.
The fact that you “don’t understand” why you didn’t earn full points for a particular question might itself help explain why you didn’t earn full points. Don’t take this personally or interpret it as a sneer. See it as a learning opportunity.
Finally, I’m here to be a mentor and instructor."
HT: Greg Mankiw