When I was in high school, I started a note from the back row of the class, which was passed and read by nearly everyone in the class. The teacher grabbed it as it went past him, when there was only 3 people left who hasn’t read it.

I think he was going to read it out to the class, but he looked at it before he read it. All the note said was that the zip on his pants was down. With all respect to him, he calmly zipped up and continued teaching.