Adults don't want to behave like they used to behave as kids. They don't want to spontaneously talk randomly about something to an unknown person, because that

Adults don't want to behave like they used to behave as kids. They don't want to spontaneously talk randomly about something to an unknown person, because that comes with risks like rejection, looking like a fool, being labelled in a certain way, associating with somebody boring/annoying/leeching, etc. Kids takes way more risks, including social risks, because they don't know those are risks. I guarantee that if you go to clubs or public places you enjoy, and you bring out the kid in you (at least the part that doesn't bring chaos), you will make friends eventually. Not immediately, but keep at it, and it will happen. However I noticed many adults don't actually want to live the process of making friends. Even without risk, they don't want to make the effort. Because here is another thing that adults don't have and kids have plenty: energy. And it turns out making friends require a ton of energy, because while you can be yourself and make friends, you cannot "be on your own" and make friends. You can't live a perfectly scheduled life and make friends. You will have to get out of your bubble, move things around in your day, welcome the unexpected, and interact. You will have to discard something in favor of it. And you will have to do it again and again because most people are not a good fit to be your friends. Kids do that all the times, without even thinking about it. Forget about the missing opportunities, it's only the tip of the iceberg, and it can be overcome by getting out of your way. I have friends that are 10 years older or younger. I made friends after my twenties and after my thirties. Hell I'm going forty yet I made a new friend 2 years ago, and we are getting pretty intimate at this point. My mother is almost 70, and she is still dating. But when I feel like inviting new people into my life (which I don't always do, right now I have closed doors, I don't have an infinite reserve of private life to share), I will invest in it. I will accept the cost. Because making friends is not free. Just like sex is not free and speaking your mind is not free. Kids don't realize the cost, and bare less the weight of it, but we are very aware of it. Making friends don't "just happen naturally" when you are a kid, there is a process. But the process is seamless to kids, while it requires effort to adults.