Little history lesson: so it turns out that in 1906 there was this little shake-up in the City by the Bay. And they discovered that it was quite difficult to navigate through the streets of a completely demolished city by the street signs (which had mostly fallen down) and the landmarks (which had mostly burnt down, fallen over, and/or sank into the swamp). So when they rebuilt, they started engraving the names of every street on its every corner.
Sometimes you find unexpectedly funny ones. There are the occasional typo. And sometimes Hayes Street seems to become a bit of a smartass.