Let’s say that every day for a semester, as the release bell rings, you say, sincerely, “Bye bye, boys and girls. It was good to see you today.”

Let’s say now that it’s second semester and your students have forgotten just how much math used to bore them not ten months ago. They’re feeling out the edges of classroom norms. They’re challenging behavior expectations a little more casually than they used to.

You may feel inclined to deliver a speech, something about how you brought them your best work today while they brought you much less than that.

But, if you really want to mess with their programming, to issue a sharp, subconscious reality check, simply let the release bell ring without your usual valediction.

The effect is sobering, contemplative, and downright funereal.