There is a gate in japan, a gate in Neiko, which is sometimes called by the Japanese the most beautiful gate in all japan; [...] but when one looks closely he sees that in the elaborate and complex design along one of the pillars, one of the small design elements is carved upside down; otherwise the thing is completely symmetrical. If one asks why this is, the story is that it was carved upside down so that the gods will not be jealous of the perfection of man. So they purposely put an error there[...].

The Feynman Lectures On Physics.