One of the more disappointing things about growing up was when I realized that "adult" is an illusion and that all the adults I had looked up to as a kid, were pretty much just big babies doing their best in life while often not really knowing what the fuck they were doing. Cobble that with unresolved issues from childhood that has manifested in stunted growth in different areas and there you go.
We are all kids. The only thing that changes except out bodies, is that we gradually learn to deal with the challenges life throws at us so what is insane at 20 is not so insane at 30 and what is difficult at 30 is not that hard at 40 etc etc.
In some ways, it is a relief to know that there is no end stage. You are a kid for life and you learn for life.