I have good news for parents: You do not need more than a few tools in your disciplinary tool-bag. One especially valuable tool, one that belongs in every modern home, is the “Doctor.” The Doctor is akin to a genie — an invisible parenting sprite, so to speak — whom you invite to take up residence in your home. But it’s not like inviting your cousin to come live with you because the Doctor takes up no room, consumes nothing, makes no mess, and moves on within a few weeks.