I had the same problem with a (large) acquainance that liked to lean back on two legs of my expensive, antique, formal dining room chairs, hands behind his head, as he pontificated on his importance at work, country club, etc. There is/was nothing that was not boorish about his speech, behavior, self-aggrandizing, or posture, so, after an hour of this, I pulled one of my dear grandmother's moves, and said, with my southern accent unneccesarily thick, "Oh, honey, I am sooo afraid that you are going to fall when you lean back like that. I'd hate for you to get hurt by splintered wood." The idiot looked at me like I was completely crazy & just kept on. A few minutes later, the chair cracked. Not one word of apology out of him. Moral of the story: there are some people who should have to apply, in a lengthy, painful fashion, to be entertained.