I would say the most "exotic" SF books. (the saga of Dune or China Miéville come to mind)

Because  they often describe worlds socially and culturally far removed from us,  allowing us to really change our point of view, and to delve into what  could be another society, another life.

Unlike,  for example, the essence of French films on complicated human  relations: no matter the situations and intrusive reflections they can  bring, we remain in a world always particularly close and realistic of  our.

We  are not thinking about the excesses and advantages of a system where  there is only 1 man for every 100 women on earth, as well as 2 new sexes  in their own right, all in a world where the cement has disappeared where teleportation is possible, nullifying distances, and where children can read the minds of their parents until puberty.
I invent, but a well-written SF book will always bring me a much deeper, uncompromising and immersive reflection.
What is daily life when you have 3 parents, not 0, 1 or 2? What reflections does this bring on our system?
How would society evolve, if our children could read our minds until puberty? What  reflection does it bring about the learning of lies, sexuality, adult  themes, on the transmission of knowledge, compared to our time?
Etc., etc…

The  films or series of anticipation, too (like Black Mirror or Electric  Dreams) bring their batch of deep reflections on the modern world,  support where it hurts, or where it feels good, on the contrary, and  allow me to to better understand what bothers me and me in our world, and how to improve it.

Dune  taught me feminism and geopolitics at 11, for example, much better than  tons of actual lectures and discussions, and with a vision and a moral /  global awareness of the issues much clearer and stronger.

Because  they push the trait infinitely farther, starting from the "finish  line", possible achievements, science-fiction works initiate changes and  reflections much faster and more global than the others, from the "starting line" of our current situation, and advancing slowly.

Without dramas, it often takes examples of enormous contrasts to create strong symbols, which push for important life changes.
And science fiction is drunk, it is often even its reason for being.
So, there would be so many works to quote, in this matter ...