convey to that person, whether we know it or not, a double message. The first part of the message is: I am teaching you something important, but you're not smart enough to sec how important it is. Unless I teach it to you, you'd probably never bother to find out. The second message that uninvited teaching conveys to the other person is: What I'm teaching you is so difficult that, if I didn't teach it to you, you couldn't learn it.
