The real reason I knew was because I had been taught that when you were going outside, it was polite to hold the door for the person after you. So, on my first day of school, when it was time for recess, I held the door for the student behind me. And the next one. And the one after that. By the time I had counted all 351 of my schoolmates walking through the door, recess was over. Nobody made eye contact. Nobody said thank you.
