He [Glenn Gould] disliked giving autographs for the same reason he was wary of writing checks for fear the results might be unlucky. But when he did give an autograph or sign a check (or any other document, for that matter), he always misspelled his own first name writing it as "Glen." Kazdin once asked him why, and Gould explained that he had discovered years earlier that once he got his hand to start forming the two n’s he couldn’t stop and would keep going and write three, so he decided to abort the exercise after one. Kazdin was skeptical. "This supposed lack of manual control is a little hard to swallow coming from the man who could play an unbroken stream of thirty-second notes faster and cleaner than any other pianist on the face of the earth."
That is from A Romance on Three Legs: Glenn Gould’s Obsessive Quest for the Perfect Piano, by Katie Hafner. This is an excellent book showing that the choice of piano really matters. For the pointer I thank Kat.