I rejected a customers request to move and clean underneath a grandfather clock. She was visibly agitated with me, argued the point a bit, "it is not heavy, blah blah". I stood my ground. She was going to show us a thing or two! She proceeded to move the clock herself. Soon as she tilted it, the weights came free, crashing through the bottom panel and destroying the glass doors of the clock.
My tech and I, without saying a word, proceeded to help her clean up the mess. Huge home, we were there all day. Never saw her again until she paid her bill. Then we never saw her again.