@nettletheelf's posts made me cringe reading them. (previous page.) This is the sort of person me and DH desperately try to avoid. A neighbour who is desperate to push themselves on everyone, and is totally perplexed and refusing to 'get' why people are not the same as them. And trying to fathom reasons why, and trying to psycho analyse people, and accusing them of being anti social and having issues. FFS! 
THIS paragraph made me cringe.
Luckily, as a veteran of many social gatherings and somebody who has had many neighbours and workmates in my 45 years, I have been able to glean some information over the years. Here are some of the things people have told me about why they don't want to socialise with people they haven't pre-vetted over a five year period (I didn't need to 'demand to know', either. People volunteered it):
Bully for YOU if you are a 'veteran of many social gatherings.' 'Whoop-de-doo! That doesn't make you any better than anyone else!
And yes I am SURE people have 'volunteered' to tell you why they prefer not to socialise with neighbours. After you have nagged and moaned and sighed at how you just can't understand why they are SO anti social.
They probably told you to shut you up!
And it's not always about 'social phobia' - what a load of shite. Me - and many others I know - have a busy social life with friends, family, and occasionally colleagues. Just because we don't party with the neighbours all the time, doesn't mean we have 'social phobia,' or are miserable and anti social.
Just because you happen to live near someone, that doesn't mean you have to socialise with them, get to know them, and be their best buddy FGS. Most (normal) people will just chat in the street with their neighbours when they see them, and will do favours in an emergency, but will generally keep themselves to themselves. Personally, I have enough friends, and don't feel the need to force people who I live close to, to be my friend.
And what is this 'no wonder people have no friends' bollocks that someone came out with earlier? Just because people don't have neighbours trotting in and out of their homes, that doesn't mean they have no friends. What a stupid thing to say.
I don't have neighbours in and out of my house, and I don't go in and out of theirs, because I don't fucking want to. It's got sod-all to do with you, so keep your psycho babble bollocks and your patronising opinions to yourself.