Loneliness is a sad human condition. Misanthropists, socially-phobic, and the overly-narcissistic might see it differently, but I feel that having a solid group of pals is an essential ingredient in my life. A few close friends, a bunch of lunch and couples pals, and plenty of enjoyable social friendlies. There are many things best talked about with friends instead of with spouses.
In tribal societies, everybody is, by necessity, connected but most Western people do not live that way now. Still, humans are social creatures. Humans also need support systems.
I once wrote a post about thinking about concentric social circles, from intimate confidantes to casual social aquaintances to work colleagues. It was a good post, but I can not find it.
Scott Adams did a brief chat about how to make friends, at the 42-minute point.
Many people could use such advice. He hints that one thing to do is to join groups, and he is right about that. You also need to have something positive, pleasant, fun, or interesting to bring to the table. Having things in common helps a lot. Alas, some people are just not very likeable, and that is a handicap.
I know people who still have friends from grammar school, high school, and college. Lifetime friends are a blessing.