Stupidity: During the film's climax where Santa and his reindeer successfully ascend over Manhattan, the sleigh's rocket engine falls off and apparently is no longer needed. Isn't it rather risky (and foolish) to assume (or hope) that the other cities on his flight path have enough "belief power" to sustain him aloft for the rest of his journey?
Stupidity: When Governor Swann is trying to encourage his daughter while she's locked within the ship's chambers trying to escape, she climbs down to a boat. Nobody in the Navy would have left a boat there, neither would Jack (and why would he, especially without anyone noticing?). The boat just mysteriously appears to help her escape.