I came across the same observation from two separate books, Ender’s Game, and The Ocean at the End of the Lane. Both child main characters are told, “Don’t worry, it won’t hurt a bit” by adults. And the MCs, immediately after, think that that is a lie, that the only times adults tell you not to worry or that something won’t hurt is exactly when you should worry or when it will hurt.
I thought it was amusing and was wondering what other interesting observations you have read. It doesn’t have to be from a wise child MC talking about adults, but it could be.
My favorite is when John Irving (by way of one of his characters) talks about how we remember things we don’t want to remember and can’t remember things we do want to remember. How it’s not so much that we have memory, but rather that memory has us. I can’t remember if that was from “The World According to Garp” or “A Prayer for Owen Meany”, which is kinda ironic.