Tyler Cowen offers this anecdote:
A story is told that Richard Wagner was walking on a street in Berlin one day and came across an organ-grinder who was grinding out the overture to Tannhäuser. Wagner stopped and said, "As a matter of fact, you are playing it too fast."
The organ-grinder at once recognized Wagner, tipped his hat, and said, "Oh thank you, Herr Wagner! Thank you, Herr Wagner!"
The next day Wagner returned to the same spot and found the organ-grinder grinding out the overture at the correct tempo. Behind him was a big sign: "PUPIL OF RICHARD WAGNER."
Which reminds me of a story a friend used to tell. I do not vouch for its truth, but it is amusing.
Allegedly, in the Italian city of Cremona, at one poin the Guarneri, Stradivarius, and Amati instrument workshops were all on the same street. One day the other instrument makers awoke to find that Amati had put out a sign claiming to make "the finest instruments in all of Italy!"
Not to be outdone, the Guarneri workers spent all day laboring on a lavish gilded sign, which they hung before the next daybreak, proclaiming that theirs were "The best instruments in the entire world!"
Whereupon Stradivarius retired to his workshop for half an hour and emerged with a simple sign saying "Best violins on the block."