I'm not sure how general my experience is (Santa Cruz is the only place I've lived in California, and it's a bit odd). But I tend to think of it as being about compartmentalization more than veneers. There are a reasonable number of people I'd chat with semi-regularly because we were both regulars at the same coffee shop, for example, but we didn't regularly socialize outside that setting. It wasn't superficial interaction in the sense of chatting just to keep up appearances or be polite or something. There is also some of that that goes on, but the people I chatted with regularly were because I actually enjoyed our conversations, and found them personally and/or intellectually fulfilling. I might even look forward to them, or visit a particular coffee shop more often if there was someone I found particularly interesting who frequented it. But I was fine leaving them at that; coffee-shop conversation partners who occupied a certain niche in my life, which didn't necessarily need to get all mixed up in other niches (and vice versa).