Aside from talking about housing and food, nostalgia about the way things used to be in San Francisco at X time is probably one of the favorite topics of conversation among the locals. It doesn't matter how long the person has lived here or the period of time for which they're expressing nostalgia (it could be a year ago)...pretty much everyone feels entitled to express it. It usually takes on the form of a strange sort of nativism...things were always "more diverse" when the person first moved to SF or when they were young or a year ago and things have always "taken a real turn for the worse lately." The speaker may say that they don't even recognize SF/their neighborhood anymore!!!

Nostalgia industry

It is strong when it comes to San Francisco. Books, tourist stuff, etc.

Rebecca Solnit is a strong presence.

Examples

"Readers' picks: Which SF structures do you miss?" SFGate

See also: San Francisco is losing its soul and San Francisco before and after and historic preservation