A couple of winters ago I turned up at a regular customers house...
Knocked on the door... The husband (who I had never met previously) answered it...
Me - "Hi - I'm the window cleaner, I'm here to clean your windows".
Him - "Oh, no not today... It's too cold".
Me - "It's OK, I can clean them on my own, you can stay inside in the warm this time".
He just looked at me and closed the door.
I cleaned the windows, left a slip, got paid, they are still a customer now.
Andy