One teacher says that she used it with her fourth graders. They read it and then discussed all that we "don't like" to do, but are grateful for, as in this passage. Then each wrote his/her own poem "I don't like __ but I'm thankful for it because it means ___."
Forgiveness. If you are angry, sin not. A lot of the times, we are chastised for anger, or for being uncharitable to others. Fair enough; that chastisement is deserved. But do we think enough about how holding onto anger and lack of charity hurts US by weighing down our souls? Think of forgiveness in terms of taking care of YOURSELF, too.