I am too childlike to be immature.
Once you realize that everyone is in the same boat, that everyone is just as insecure and childlike as everyone else, that all these jokers in D.C. ruining our world are just greedy kids grabbing for marbles - I think that realization means you're an adult.
'Painting like a child' isn't a negative for me... it's something only great artists can really achieve. The childlike quality of some of Picasso's drawings is precisely what makes them so masterful and extraordinary; the ability to express complete visions, feelings and portraits through a continuous line.