Turned up the other day to clean the windows of two houses opposite each other. Always start on the same house, and while I am cleaning the owner of the other house always sees my van, comes out and pays me in advance. On this occasion he approaches me as usual, pays me and says don't worry about doing the windows this time, the weather is going to change. I tried to give him his money back but he insisted I accepted because I had turned up anyway, even though I live about a mile away!