Arthur Conan Doyle, creator of Sherlock Holmes, once traveled to Switzerland. When he arrived, he took a taxi and the driver told him he wouldn't charge him if he autographed a book.
Conan Doyle, surprised, asked the taxi driver how he knew he was a writer, and the taxi driver replied: "Easy, your shoes are covered in dust that isn't from here. From the pattern of your shoes, I see that they are English shoes. So it's English dust. You have an ink stain on your toes, so you are a writer, a British writer."
Shocked, Conan Doyle replied: "You are smarter than Sherlock Holmes."
"Yes sir, and your suitcases clearly have Arthur Conan Doyle written on them."