It's called the Dunbar number, and it varies:
As I understand it, Napoleon inspired such loyalty in spite of how he treated his people because he could greet everyone by name and ask how their wife Elaine was doing, etc. It made everyone feel he caredabout them personally. I had similar talents when I was younger but never really knew what to do with it as I was a homemaker, but I am familiar firsthand with the types of emotional responses it inspires from people.
In between small and huge you get this ackward feeling anonoumity which stresses you, you get shopping malls out of town, something impossible in Manhatten for example since driving hours to do grocery shopping is just inconvinient. And all that is, I think, not natural to us humans. where this limit between big but not big enough lies, i don't know, maybe it depends on culture... but that's something I tend to see all the time i spend time real big cities. But maybe it's just me.
There's a long video on Prarie Home Companion (on YouTube or Hulu), following Garrison Keillor around as he does the show, and at home in both Minnesota and Manhattan. As he's going through New York, he observes, as you've noted, that it's really a collection of villages.
I've had very similar experiences myself.
I have looked around and asked around a smidgeon for online resources related to San Diego. I am getting the impression there isn't all that much, at least not anything really good. I wondered if people would be interested in having something better. I am still toying with the idea. At one time, I wanted to go into urban planning or something related. Urban planners tend to be career bureaucrats, many working for government. That is not my comfort zone. Before life interrupted my career plans, I was increasingly wondering what that "something related" part might be. I am wondering if I might be in the process of stumbling into it currently.
He was a very effective salesman.
(BTW the company still exists, http://cmtengr.com/ is their website. My grandfather was Ray Tilly.)
My friend told me that he could remember faces well, but that more often than not it contributed to awkwardness when he could remember the other person's name, but the other person couldn't remember his.
I have been told that, in a sales context, this actually helps. It fires off some sort of feeling that you need to make up for the social faux pas.
(I am truly awful at remembering faces and names - so have never had the opportunity to find out myself :-)
The awkwardness is easily removed simply by greeting someone by their name and repeating yours without giving them a chance to 'not remember'.
"Greg! Hi! Mike. How's Sarah? Did you find your dog in the end?"
My ex was career military. He relied on nametags. My son has done some reading on faceblindness. Faceblind people often identify people by voice or some other trait instead of by face. Sometimes it goes largely unnoticed because they find another means to recognize most people reasonably quickly.
In general, the sooner I get it out there, the better off the conversation goes. The worst is when I get their name and I still don't remember context. I mean, an ordinary wearable rig with a twiddler and an email lookup would take care of that.
For me, getting to be on the other side of the equation has been a growth experience. People with the kind of innate abilities I had frequently become what I view as con artists and master manipulators. I think they don't necessarily intend for it to be that way. They just don't necessarily understand what it is like to be at the disadvantage. I hope more of my innate abilities return. But I cherish the lessons learned from walking a mile in their shoes. It has made me a better person.
Peace and best of luck.