Ok. Here is a big one.
Citizen Kane?
One thing a lot of people don't know: the ending is actually a very, very nasty inside joke. Somehow Orson Welles learned that "Rosebud" was the pet name that William Randolph Hearst gave to his wife's clitoris. It has nothing to do with the stupid sled, which is just a Red Herring. Most lefty critics were in on the "joke."