" the clarity of your guidance gets measured at the other person’s ear, not at your mouth. That’s why it’s best to deliver guidance in person. You won’t really know if the other person understood what you were saying if you can’t see the reaction. If you don’t know whether what you said was clear to the other person, you may as well not have said it. "

― Kim Malone Scott , Radical Candor: Be a Kickass Boss Without Losing Your Humanity