This year in the first week I sat each chorus down in a circle. I handed one student a piece of paper and asked them to pass the paper around the circle as quietly as they could. The silent concentration in the room was amazing.
When the paper got to me, I quickly and carelessly crumpled it up. Many of the students were visibly shocked.
There was a double lesson here: It takes the whole chorus to build something, and only one person to tear it down.