This book changed my life. I read this book when I was maybe 17? And read it again last year, a decade and a half later.
The most powerful lesson I learned here is what anthropologists call cultural relativism. This book also taught me that everyone is under the influence of Mother Culture and her stories. I think internalizing this can help a lot with understanding other people, building self awareness, understanding politics in general, and also history in general.
There's a narrative here about ecology and generally making the world a less shitty place which is nice too, but not the primary value-add IMO (although it's unique in proposing cultural transformation as the solution).
Nevada by Imogen Binnie was another. I read it when I was working through questions about my gender. It's dark, funny, beautiful, and brutally candid account of the (a) trans experience.
Ursula LeGuin's Earthsea series follows these closely.