It's probably the most universal criticism possible. "Stop being so immature!" Everyone has probably heard or used it before.
But what do you think the accumulation of experiences through life and the stages you are supposed to go through actually are?
It doesn't matter how old you are right now. I'm not old myself (even if I fear getting closer to 30 every single birthday, the beginning of the year, and the end of December, let's not even get started over how crazy I'll be nearing 40) what matters is what observation(intentional or not) has shown you.
I think it's about investment and submission.
It's not about gaining the capacity for empathy, I became less emotionally intelligent the longer I live.
It's not about your preferences, aside from how that relates to submission. I still cannot handle coffee in any form and only eat what I want rather than what I should.
It's not about feeling responsible for your actions, to say that children don't do that already is taking them all and demonizing them (not even dehumanizing them) because of their age.
I don't know why adults are telling kids those things. It's like they were either complete shit as kids themselves or that they weren't ever young.
It's about investment of effort, because you're thrown into an environment where you will be paying for everything yourself, getting the money yourself, fighting to keep your social relevance, not starting what isn't worth it, managing time to suit your needs rather than your desires, living life as someone who is aiming for something far beyond rather than someone that is happy with whatever comes by, and so on.
It's about submission to weakness, because you have to give up what you wanted for what is viable, because the consequences for defiance to social conventions will become that much heavier, because you have to rely on guile rather than strength, because you have to concern yourself with everyone around you even when you're having enough problems just dealing with yourself, etc.
It's that time where you have to be willing to accept that everything around you will change and that you're only an insignificant commodity that will desperately try to achieve whatever it can to continue finding life worth living as you survive another day rather than taking nice things in life for granted.
The apex of all that, of course, is in having children.
Taking all the responsibilities. Spending all those resources. Making sure that they will be as ready as they can be when they will have to deal with what you have to deal with now. And showing how pissed off you are when your child doesn't seem to be living up to being worth the investment, hoping every day that one day it will pay off, yet always needing to be ready to deal with the consequences for when they won't be.
The criticism rings a lot heavier when I realize what exactly they're telling me to become. And that probably isn't even everything coming.