That's the thing I find so disappointing about adults, myself included too often: the loss of a sense of wonder. Sure, I know about how earthworms move (for example), but a kid doesn't, and when he sees one for the first time, he's fascinated just the same way I was the first time I saw it. I try to respond to kids in those sorts of situations differently than what I usually got: which was something to the effect of "yeah, so?"
This piece does a good job of recognizing and respecting that sort of wonder, even though the speaker has grown beyond it. That may be the core of why I like it, but I don't know if I would have been able to put my finger on it without your comments, zelda_pinwheel.