Then one day you realize that, they have no idea what they are doing. You think that might be a comforting thought but it ends up keeping you up at night.
I had been waiting from pre-teen, through teenage years, and past my young adult years. Wonder, waiting, hoping I would someday feel like I had "grown up" and was an "adult" now.
That's the trick: it never happens. There's little difference between a "kid" and an "adult" besides obvious physical maturation. You just get new things to juggle and new worries. Bills and job instead of homework. Kids and coworkers and friends (if you're lucky) instead of HS drama. I still don't feel that much different at the core than I did at ~18 and that was 19 years ago.
Funny story, instead of referring to groups of adults as " hey guys," I like to refer to them as "hey kids." You know how many grown adults I've had object to this? Zero. Not one. Ever.
The real mind fuck for me was the realisation that we're all just blobs of genetics navigating ourselves through a cold and uncaring universe and that free will is an illusion.
People hate the idea that they're not in control of their destinies.