Formative media experiences I don't remember often:
- A book about a kid who learns to trn into a plant, ie, photosynthesize. I read it in the dark in elementary school while school was subjecting us to the first Star Trek movie.
- Some story in a middle school reader in which Earth folks (a family IIRC, as the protagonists of the particular story) move to Mars, but the landscape or water or something makes them turn into Martians, using Martian language etc. This is what I (sometimes) think of when the word grok comes to mind, just from the similarity of context since I've never actually read any actual Heinlein.