The signs, property of the city, are there to tell residents and tourists alike to keep nothing of value in their automobiles thanks to a number of car break-ins over the past few years. Everyone, it seems, has a story about a theft or knows someone who had a close call. And if crime isn’t the favored topic among the city’s affluent and shrinking middle class, it’s the rampant homelessness and drug use, now spilling out from the foreboding Tenderloin.