The best example I can come up with off the top of my head is John Huston in Chinatown. Nicholson’s character’s name is Jake Gittes and he pronounces it as “git-tess” (maybe “git-tiss” for us Southern types) in an obviously two-syllable name. Huston always mocks him by saying “Gits” or “Gitz” or some other one-syllable thing.
What bugs me is that Noah Cross (Huston’s character) would hear the name as Jake says it when introducing himself. But Huston (the actor) would more than likely encounter the name first by reading it in the screenplay. He could be forgiven for mispronouncing it to himself as it appeared on the page, but Polanski should have corrected the mispronunciation for the sake of realism.
To my ear, that has always been an affectation that rankled me.
Any other examples like this? Other examples of silly shit that annoys you in otherwise fine films?