I definitely agree on the fact that things tend to be easier in a bigger city; sure, you might not be in contact with people as easily, but for someone a bit different, the larger number of people tends to dilute the changes of gossip, which, as someone aptly mentioned above, creates social bond. Sometimes I catch myself fantasizing about moving to a quieter, smaller town when I'm older... and then I remember I would be the talk of the (small) town if I did.
Anyways, back to the central topic:
I've never had difficulties making BUDDIES, as in if I identify someone who has something in common, and I feel that interest or characteristic is strong enough to start a conversation, I will have no problem going to them. So I could very well initiate a conversation on the subway over an item that reminds me of a special intetest... meanwhile, I could be working for weeks in the same place as someone else and never utter more than the conventional greetings if I don't feel this thing in common, simply because it wouldn't even cross my mind.
I'm not as good at making friends, and I'm terrible at keeping them. It's like I know the theories of friend maintenance, but I'm somehow at a loss when it comes to apply that knowledge in a practical manner. The fact that I also need long periods away doesn't help, either.
Another thing I've observed over the years:
I've never had a best friend. I don't even know why people feel the need to rank them, is there a friend competition somewhere? But friendship in the outside world seems like I'm making the current friend a special interest, and then that friend is the only friend I will hang out with. My boyfriend used to joke that for 6 months to 2 years, he'll hear the same name all of the freaking time, and then suddenly poof! No further mention of the person, ever. Come to think of it, this almost looks like what most people would do with a romantic partner, except there's no romantic interest involved in my case. I can tell from observation that this is not how most people go about friendship, but I'm not good at balancing the expectations and presence needs of various people at the same time. And when I do make friends, or at least people who are more than buddies, they tend to be such different people to one another that I can't have them in the same room (I've tried once. This is how I found out that one was severely homophobic, which I had never had any reason to suspect, but apparently meeting a tattooed lesbian was a bit much for him, and as I was realizing that we were on the verge of a disaster, another friend arrived dressed as a cat. No, it was not a costume party. I'm telling you, the people I mingle with are too different, they all need their one-on-one time).
That last bit is the opening scene to your sitcom
How brilliant.