"Most authors indulge in little eccentricities when working, and, if the time should ever come that your name is brought before the public notice..."

"... it would be advisable to develop some whimsical habit so as to be prepared for the interviewer, who is sure to ask whether you have one. To push your pen through your hair during creative moments would be a good plan; it would reveal a line of baldness where you had furrowed the hair off, and afford ocular proof to all and sundry that you possessed a genuine eccentricity."

From "How to Write a Novel: A Practical Guide to the Art of Fiction" (1901).