How SILLY can you get?

One day a husband came home from work in the middle of the summer and his wife was in the living room painting the walls with a roller and brush but she was wearing two different coats. Her nice new fur coat on the inside and a plastic raincoat on the outside. The husband immediately blurts out, "What the heck are you doing honey, why are you wearing those coats? Its 89 degrees outside, are you losing your mind?." And she replied, "  No, Honey I just read the can and the instructions said to put on two coats for the best results. Why? Should I only put on one?