“I suppose,” I remarked, “that, homely as it looks, this [hat] has some deadly story linked on to it — that it is the clue which will guide you in the solution of some mystery and the punishment of some crime.”
“No, no, No crime,” said Sherlock Holmes, laughing. “Only one of those whimsical little incidents which will happen when you have four million human beings all jostling each other within the space of a few square miles. Amid the action and reaction of so dense a swarm of humanity, every possible combination of events may be expected to take place, and many a little problem will be presented which may be striking and bizarre without being criminal. We have already had experience of such.”
– The Adventure of the Blue Carbuncle, A. Conan Doyle.