As a native Angelino, moving to North County SD was a culture shock for me.
1. Compared to LA, the job market here sucks (except, perhaps, for techies). The pay is about 10 years behind LA for the same jobs.
2. Very little “diversity” in SD. Growing up in LA, one doesn’t even realize how many different culture exist there. As long as there isn’t one really dominant culture, it seems everyone pretty much gets along when you see a big variety of people. It lends itself to a more energetic, buzzing, exciting lifestyle, IMHO. San Diego seems to be white and brown (Latin Am & Asian), with not much else.
Now, when we visit LA, it’s just so much fun to go out and “people watch” and hit all kinds of coffe shops, bars, restaurants, events, etc.
I imagine the Bay Area is similar in this respect (as NY would also be, I’d imagine).
3. The more “cosmopolitan” cities have so much more to do! Again, North County really lacks in this regard. In LA, you could go out to dinner every night of the week and never hit the same restaurant twice. Every kind of food (again, with the culture thing), and it’s all easily accessible, since it’s so densly packed, you can walk to a lot of places.
4. San Diego has no trees! Many of the developments here are barren and ugly moonscapes with tiny lots and huge McMansions — largely because everything is so new, and the developers were just trying to maximize their profits without any regard for the lifestyle of the future residents. In North County, it’s difficult to walk anywhere, even to the store, as you have to cross 8-lane roads and things are not built in a pedestrian-friendly way at all (few/too small sidewalks that end abruptly in awkward places, etc. and are located on VERY busy streets).
The way the communities are planned in SD (again, North County), all the traffic is diverted to a painfully few main arteries with very high speeds, making it difficult to get around without cars. I prefer the “grid” structure where traffic is spread-out more and the streets are more pleasant for walking.