You wanted to read the book, you were excited to crack it open, you came into it with good faith and anticipation… but you ended up dnf-ing it. Which book and why?
Mine was The Maid by Nita Prose. It was for my book club and looked like a fun murder mystery. Instead I got instant manic-pixie-dream-neurodivergent-girl vibes, and I noped out before the crime scene was even found.
I don’t know if DNF really applies, but I picked up a fantasy book for dirt cheap (one of those dollar bins at a used bookstore) without knowing anything about it, and never started it when I realized it was military fantasy (not my genre) and told in first-person present. Gave it a few pages before moving onto something else.