As distinguished from continuity errors or inaccuracies. I mean inconsistencies in the storyline. I can think of three:
The Wizard of Oz: Dorothy runs away in Kansas to save Toto. When she meets Professor Marvel, he immediately makes her for a runaway, and prompts her, “You want to see new cities, new mountains, new oceans!” Dorothy agrees because it’s simpler than admitting that she’s running from the law (like he’d care, but she’s a kid). Then, at the end, Glinda asks her what she’s learned, and she tearfully replies that “If I ever want to go looking for my heart’s desire, I needn’t look further than my own backyard!”
Except, not! The lesson learned should have been “Don’t run from trouble; it always follows!” Which it did. She was never looking for her heart’s desire; she always wanted to get back to Kansas (silly hick! Baum was right to have her go back to Oz!). If there was any heart’s desire, it was simply keeping Toto; wanderlust didn’t come into it.
(I might also point out the inconsistency in the Scarecrow being intelligent despite not having a brain, the Tin Man being (an) emotional (wreck) despite not having a heart, while the Cowardly Lion really is cowardly. Even when they were storming the castle, he asked the other two to “Talk me out of it.”)
Saving Private Ryan: How can Ryan remember the landing at Omaha, most of it from Miller’s POV, when he wasn’t there at all? Maybe, possibly, a buddy of his brother who was killed there filled him in, but that kind of verite flashback should come directly from the object of the fade in/out.
Metropolitan: Early in the film, Christoper Eigeman tells the redheaded guy that it would be wrong for him to withdraw from the group that he’s been drawn into, on the grounds that the girls are counting on the guys as escorts, and without them, the girls would have no social life. Except, after the deb season ends, very abruptly we see one of the girls on a date with a middle-aged record producer, another leaving for a date with a guy “None of you know, and I’d like to keep it that way,” and the other two at a weekend house party with Eigeman’s nemesis. So much for their not having social lives, or knowing anyone outside that social circle!