I’ve always wondered why some people limit themselves to a certain amount of people rather than expanding their acquaintance circle for networking/potential friendship purposes.
The way I see it: Even though we all have a choice of who we want to interact with, who knows what those people are like? That’s why I try to expand my acquaintance circle, to an extent. I see nothing wrong with being open, but it all depends on if other people are willing to do the same.
We were recently invited to a neighborhood “party”, an invitation we declined because we have plans that night with friends. I pointed out to my gf that before we make any new friends, some of our current friends will have to die. 
IME, relationships (platonic or otherwise) require maintenance. For the relationship to be healthy, the people in it need to interact with each other on a reasonably regular basis. Such interaction may be in person, on the phone, or in cyberspace, as long as there’s some sort of connection that gets exercised now and then.
A person may be open to as many relationships as they think they can maintain, subject to their own standards regarding the health of any of those relationships and the amount of effort they’re willing to put into maintaining them. ISTM the difference can be ascribed to extroversion/introversion: an extrovert may be willing to pursue/maintain far more relationships than an introvert, and people vary as to where the exist on the extrovert/introvert spectrum.
I’m pretty extroverted; I usually enjoy getting to meet new people.
But, I’ve discovered that most of my closest friends are exactly the opposite – they’re introverted (some of them greatly so). For them, meeting new people is somewhere between “a chore” and “very uncomfortable.” Many of them don’t enjoy going to parties, or mingling with people that they don’t already know.
Also, several of them suffer from various levels of social anxiety; they are far, far happier sitting at home, in their comfort zone, and interacting with their small circle of friends and family.
This is one of the big reasons, a lot of people already have enough friends. Friends want to go out to dinner and events, and hold parties, get married, have children, and then those children have christenings and confirmations and bar mitzvahs and graduations and eventually get married which extends the cycle, sometimes branching into multiple paths.
But I think most adult friendships are just a matter of time and opportunity anyway. You will meet people, talk a little, occasionally find something in common, and over time you can grow closer. If that’s not happening you have to get out more and start doing things you can invite others to do with you or participate in group activities to get closer to people.
My wife and I have lots of friends. I have close friends that we see regularly, that we travel with, etc. I have friends through work, friends through our kids school, etc.
My wife has a core group of about 6 women that she sees regularly. There are three that they take girls trips a couple of times a year, and then annually the husbands tag along for a couples trip. It’s a fun group and we all get along well, and enjoy similar things.
Sartre said it best: “Hell is other people.”
Might be related to Dunbar’s Number.
Also known as “the Monkeysphere.”
Some of us hyoomons are just shy, that’s all. Don’t ask why.
I have a Dunbar number of like 6.
I don’t have more friends because the majority of people I meet strike me as predators looking for money or someone to listen to their weird political bullshit (left or right). Nobody wants to just hang out and frighten golf balls or drink a few beers. Fuck 'em. I have enough friends and I don’t want any more.
There are only so many hours in a week and i barely have enough of them to keep up with my current commitments. Why would I be in a hurry to add more. One of my friends was laughing because we finally accepting having dinner at his house for the first time in months. Like he said we turn him down 90% of the time. If we had more friends we’d have to turn them down more often.
The only friends I’d entertain adding are the parents of my kids friends so we can hang out while the kids do or exchange babysitting.
Introverts find relationships tiring. Some are rewarding, but all are tiring. New relationships are not a universally happy exciting thing like they are for extroverts, they are a calculated investment of energy with the substantial risk of it being a dead loss.
America is an extroverted culture, perhaps the most extroverted the world has ever known. Extroverted behavior is “normal” and rewarded, introverted behavior is at best puzzling. But there are a lot of us.
Short version: people are different.
It also might be that you’ve flagged yourself as someone they don’t want to spend more time with. As a white guy who appears straight and not anti-religious, I often bump into people who assume I’m significantly more normal and conservative than I am. If you let fly comments that make me think you’re not going to be cool with the fact that I am a non-christian with multiple partners, one of whom is non-binary and another of whom is non-white, then you’re not going to see any of that but you’re also not going to get invited into my personal life or my other activities.
At a certain point, you feel “I have enough friends. I don’t really need or want more.”
If at that point, someone wants to introduce you to someone new, that new stranger has to be someone ***truly ***compelling or interesting to be worth it.
There’s lots of reasons why I make no effort whatsoever to meet new people, and am okay with my lifestyle where I never ever meet anybody new.
I have a pretty bad memory for names and faces. So you’re going to be a blank nobody nothing to me unless I spend time with you regularly, at least weekly, for more than a brief conversation. That’s a pretty big time investment, and I’m a pretty busy person who values my remaining free time.
I hate crowds - among other problems if two or more people are talking at once I can’t understand any of you. My brain can’t parse it. So most venues for meeting people are unpleasant and completely ineffective for getting to know somebody since I can’t understand a thing they’re saying.
I’m weird, and thus assume everybody will hate me. Or, if they don’t hate me, we’ll have no shared interests and we won’t have anything to talk about, and it will get awkward and just peter out. It’s certainly happened before.
I’m also, like, 80% satisfied with my current friendset, which consists of precisely one friend plus my family (which supplies about 3.5 friends, going by people I actually interact with). These 4.5 friends are all pretty good friends and I don’t feel the need to trade them out. Well, mostly. I mean, if I could develop an actual romance I would happily slot such a person in, even if that required me to reschedule everybody else. Of course I’m not actually going to find a romance on account of the above things, so since that’s not happening my current friends are cool, and don’t need replacement.
ETA: Oh, and I’m also an introvert, so meeting people, even my current friends and family, is costly from an energy perspective as well as a time perspective. Meeting new people sounds like a high cost, low chance of a return proposition.
The internet provides provides an unlimited capacity to chitchat with people.
Maybe they avoid meeting new people based on their experiences with old people.
The perhaps interesting thing about interacting with people on the internet is that it doesn’t burn my limited introvert pool of ‘social stamina’.
I’ve joked about thinking that everybody on the internet is a bot, but at some level it’s apparently true - I really don’t think of you people as people.
But probably not the same children.
I was surprised to learn that this sentiment appears to be quite popular.
