3. Iron Man 3 (2013)
The Twist: Iron Man meets his match in his most dangerous enemy yet, a terrorist calling himself the Mandarin, as played by Ben Kingsley... but towards the end of the movie we discover that the Mandarin is actually the character played by Guy Pearce, Aldrich Killian, and that Kingsley is actually playing an actor named Trevor Slattery.
Why It's Unpopular: Trevor. His name is Trevor Slattery. That's why nobody like this twist: because the filmmakers made the Mandarin into a kind of joke. That aside, isn't this just a pointless compromise of an iconic character for the sake of a laugh and a plot twist that doesn't really benefit the story on the whole?
Why It Deserves More Credit: Hey, at least the filmmakers tried to do something different, and I don't think anybody could say that it wasn't nice to see Ben Kingsley playing two
very different characters. But the real reason that this doesn't get enough credit is because the character of the Mandarin is sorely outdated, and writer/director Shane Black managed to create a new and interesting way to deal with this guy. It didn't please everybody, but it fit well with the tone of the movie - even if some people did think it was much too jokey overall.