For that specific song, rather than the general answer ladytabitha got, it's about...

things like that there are things about being child like which I think people should want/try to keep. Like belief in magic. And wonder. And hope.

Joy in beauty and new things and exploration.

It's not an accident (although I didn't notice it until now) that the two things I linked were that song and the post of australian_joe's. Those things are important to me, and they often seem like they are not important to far, far, far too many people.