Who Americans Spend Their Time With (theatlas.com)
Data scientist Henrik Lindberg has a series of fascinating charts based on data from the US Bureau of Labor Statistics that show who people in the United States spend their time with over the course of their lifetime. Check out the charts here. From a report on Quartz: Some of the relationships Lindberg found are intuitive. Time with friends drops off abruptly in the mid-30s, just as time spent with children peaks. Around the age of 60 -- nearing and then entering retirement, for many -- people stop hanging out with co-workers as much, and start spending more time with partners. Others are more surprising. Hours spent in the company of children, friends, and extended family members all plateau by our mid-50s. And from the age of 40 until death, we spend an ever-increasing amount of time alone. Those findings are consistent with research showing that the number of friends we have peaks around age 25, and plateaus between the ages of 45 and 55. Simply having fewer social connections doesn't necessarily equal loneliness. The Stanford University psychologist Linda Carstensen has found that emotional regulation improves with age, so that people derive more satisfaction from the relationships they have, whatever the number. Older people also report less stress and more happiness than younger people.
I am reminded of the saying: He who has many friends has none.
Great minds think alike; fools seldom differ.
Until your 20s or so, 'friends' are usually the least objectionable acquaintances from school. Now, that's potentially a large pool of people so you can get lucky and find real friends in that group.
For a brief period in your 20s, you may form some friendships with coworkers or somebody you meet socially. Usually a limited pool of people, and that's the pool you're choosing a spouse from.
In your 30s (if you have kids), your friends are the parents of your kids' friends.
It often isn't until retirement that you're actually free to form relationships with someone based on common interests instead of common circumstances. And guess what? They're all old and moderately set in their ways so the odds of a friendship forming are lower. And they're going to die at a higher rate than in your youth, so there's that, too.
We spend our school days trying to figure out where we are in the social structure of our world.
That effort, once we hit puberty, turns into the search for a suitable mate.
By 25 - according to the /general/ development of humans, not the last 70 years of extended fertility and 'modern' prioritization of career over family - you should typically be done seeking a mate, and into child raising.
Once you're done raising children, you're more or less reproductively superfluous and should die off all else being equal.
Plus, around your mid 20s-early 30s you start realizing that so very many of your so-called friends are really assholes you put up with, and choose to no longer do so.
By your mid-40s you're starting to suspect that MOST people are really assholes, and ultimately there are just a few people (optimally, your spouse) that you really enjoy spending time with, if anyone.
-Styopa