A brief thank-you note has an outsized impact

DEAR ABBY: Some time ago, you printed a letter from a grandmother who said she was changing her will because neither her adult children nor her grandchildren ever wrote her thank-you notes when she sent a gift. I had taught my son the importance of writing thank-you notes, but he wasn’t doing a very good job of completing the process. I cut out the letter from your column and sent it to him.