Curiosity, wonder, play.
The example set from a child is a gift to us, and a reminder to cultivate these traits, rather than snuff them out with adult conformity. We can be responsible, kind, knowledgable, on time, and mature, while still maintaining participation in this life and its experiences. Basically, we don't have to numb our inner kiddo to be thriving adults. I think maybe it’s just the opposite.