One friend becomes a Doctor and stops acting. One friend becomes a life insurance salesman and stops painting. The creative guy who loves people becomes a Doctor and ends up after years of study tired of Medical politics.
And by letting go of things we love we live in parallel. We go off on different directions. We make new friends. We experience new things. But our new friends do what we do, and often think like we think. The gap from our old friends may not be that far, but we cut ourselves off from trying because with time and specialisation we forget our common ground.
How long would it really take to find common ground? We don't know. Our default isn't to be open to learn. Our default is to just accept the way it is. Time is limited so we choose.
Kids don't choose. They play. They explore. They fail. They succeed.
Kids rock. Just saying.