When I was in college, my then girlfriend texted me that she was watching Jojo Rabbit. She knew it was one of my favorite movies, and said that she loved it too. She was talking about how Scarlett Johannson’s shoes almost have their own personality. So I said,
spoiler
yeah, it’s devastating when you notice her shoes on the hanging body.
Turns out she had paused the movie to make some dinner, and hadn’t seen this part yet. Needless to say, she was PISSED!
I accidentally spoiled Dumbledore’s death for a college roommate (she was a late adopter and it was probably 5+ years since the book came out)