Snooooopy, that’s because it is completely alien, and just a San Francisco thing. I’ve lived in California for the majority of 29 years and it still sounds bizarre. I never heard it til I got here.
It is?? The only people i’ve ever heard using it have been from the East Bay or the South Bay.
Of course, in my experience most San Franciscans (Franciscans? Friars?) look at the East Bay in the same way that most Manhattanites look at Long Island and New Jersey shrug