“I don't want to go to school and learn solemn things. No one is going to catch me, lady, and make me a man. I want always to be a little boy and to have fun.” Peter Pan
Distinctions are what children crave. That's is why they always ask questions. Very rarely do we encounter a child who is perfectly content with an ambiguous statement unless he cares nothing for the subject at hand. Distinctions make us feel safe. That is why we have secret passwords, code names, and complex explanations for our imaginary games. Which is more fun: playing "space man" or playing "Francesco, captain of the spaceship serenity, on a dangerous mission to a dying planet to rescue the ambassador of Alderaan from a race of evil rat people"?
The children would care very much if their grown up friend was childish or childlike. They may not use the same words, but they would care very much about the distinction.
Our generation doesn't know what to do with the idea of growing up. But think back to the people we dreamed of being when we were young, they were all grown ups! Superman is a grown up, Cinderella is a grown up, so are astronauts, rock stars and explorers.
None of us wanted to be Peter Pan until we reached the age of nostalgia. Your very difficulty with growing up has nothing to do with childhood, it has to do with being in your twenties and not having met your healthy grown up self yet.
The key is not to avoid growing up. The key is to avoid being a thoughtless boring person and work on being an awesome person. Children want to hang out with an older person who can show them cool things, teach them about life and be a pillar of stability. The routine, boring life has nothing to do with developing into the human you were meant to be.
This is my defense of " growing up".