9. Who's Who? - Who Framed Roger Rabbit
This wasn't an intentional mistake by any means, because the filmmakers opted to remove the question mark from the title having learnt that movies with more punctuation in their titles make less money (horrifying, but true). Still, it was a misjudged move, really, because
Who Framed Roger Rabbit has to be read as a question to make sense. That's to say, without the question mark, the title is implying that somebody
called "Who" framed Roger Rabbit. If you're not aware that it's supposed to be read like a question, how would you know otherwise? Nowadays the movie is famous enough so that people don't need to worry about this, but it still makes no sense.