I was going into town one day and had gotten as far as the gate when I realized that I had odd shoes on, and one of them clean and the other dirty. There was no time to go back. As it was impossible to clean the dirty one, I decided that the only way of making myself look less ridiculous was to dirty the clean one. Now would you have believed that this is an impossible operation? You can of course get some mud on it but it remains obviously a clean shoe that has had an accident and won’t look in the least like a shoe that you have been for a walk in. One discovers new catches and snags in life every day.

C. S. Lewis, letter to his brother, 21 April 1940