I saw the TombRaider movie with my dad, and he apparently thought the movie came first. Of course, the gamer in me was quick to correct him.

This troper got a weird look from a friend when I mentioned AHistoryOfViolence was a graphic novel by the man who created JudgeDredd.

I was once in a bookshop and there was a young man and his girlfriend in the little kids' section, looking at a Winnie-the-Pooh book. The woman actually remarked that Pooh was naked! She'd obviously only seen the films. Also, most people I meet have no idea that Mary Poppins was a book, or that Peanuts was originally a comic strip.