Lo HaBaishan Lomeid, Velo HaKapdan Melamed

This insight dawned on me around dawn.

The mishnah states that a kapdan cannot teach and a baishan cannot learn. These rich words roughly mean that an overly strict and impatient person cannot teach and an overly hesitant, afraid, embarrassed person cannot learn.  This is usually taken to mean that when teaching one should not be overly strict and when one is a student one should not be overly shy.  But that's not what it says.  What it says is more global; one whose general personality, not just the posture they put on in front of a classroom, is to be impatient cannot successfully model for and influence others.  And one who generally, not just when they are stuffed into a student's seat in a classroom, feels embarrassed and insecure cannot successfully learn life lessons.

Had the mishnah  been speaking solely about a classroom situation it would have stated the context, saying something about strictness or shyness regarding "a student in a Bet Medrash," "a teacher in a school," etc.