A good-news environment requires the teacher to model repentance. Not every sin is appropriate to share with students, but they need to know some real and ugly sins I struggle with. They need to see how, in Jesus, I find forgiveness and the power to repent. This helps the naughty kids deal with their misbehavior—but it’s even more important for the teacher-pleasing kids who arrive trying to show how good they are. It tells them not to be proud or put their hope in their own goodness. It points all kinds of kids to the Savior.