It is a peculiar yet not unenjoyable experience to know a bit about a story going in, carrying expectations of a key plot point or two and trying the whole time to recognize them, only to much later realize that you’ve been reading/watching something very different, and that you’ve accidentally gifted yourself with a relatively unique experience of the story by seeing it through an unintended perspective.
The first time this happened to me was when I first saw The Matrix—I had seen the trailer for The Thirteenth Floor and thought it was going to be that. I still haven’t seen that.
Currently I’m ~3/4 of the way through Halcyon Years by Alastair Reynolds and it took me until a good third of the book until realized that I had started it instead of There Is No Antimemetics Division by qntm. (I’m enjoying Halcyon Years so far. Still haven’t started the book I meant to.)