Where's my sock? or Sock on, sock off

Back when I was in high school, a long time ago, a more restrictive dress code was instituted, requiring, among other things, that socks be worn.

Not long after this, I was sitting in class one day when I felt coldness on one of my legs, near the ankle. I looked down and discovered, to my horror, that I had only one sock on. To make matters worse, I was sitting at the very front of the class, approximately in the middle.

The teacher, a man, was on the far right side of the room, standing up, talking to the class. After a while, he turned and walked to the left, I guess to talk to somebody over there. As he passed me, he frowned at me but didn't say anything.