- Trolls are commonly thought of to live under bridges. What is the name of the city the boxtrolls live beneath? Cheesebridge.
- Why is Winnie obsessed with boxtrolls and their lore about being monsters? If you think back to earlier in the movie, you remember Snatcher announcing curfew for all of Cheesebridge, mentioning the boxtrolls have a lair with "Rivers of Blood and Mountains of Bones". Later, in the boxtrolls cave, Winnie says those exact words, verbatim. Perhaps hearing the curfew announcing from outside every night has practically been her lullaby since infanthood.
- When Winnie encounters Eggs a second time, she asks if the boxtrolls ate his family, and if they let him watch... or rather make him watch. At first, it seems like she's trying to cover up a sadistic side to her. But it actually indicates she must imagine her neglectful parents being eaten by boxtrolls. And her saying "did they make you watch" is her recognizing that Egg's parents probably weren't as bad as hers.
- When Fish explains what really happened to Egg's father, there's a bit of foreshadowing as to why the present day Mr. Trubshaw is obsessed with jelly. Look carefully when Trubshaw lets Fish hold his son. See that jar he picks up? It's a jar of jelly jam.
- If you think about it, Mr. Trubshaw has a point about how his son is a "new species" all his own. His son "evolved" beyond Nature vs. Nurture. Eggs was born a human (Nature), but he turned out less selfish than most humans in Cheesebridge. Eggs was raised by boxtrolls (Nurture), but he wasn't as cowardly as they are. So he's something else in between.
- As part of the movie's theme, Eggs isn't able to convince the people of Cheesebridge that boxtrolls are harmless, simply by telling them so as a regular-looking boy. In the end, what really convinces the people is when Eggs is his true self, a "boxboy" embracing the boxtrolls like they family they've been to him. You define you indeed.
- Mr. Trubshaw favorite food being jelly isn't just because he's been driven crazy. It's somewhat symbolic of how he's different from the rest of the citizens of Cheesebridge. You have the people of Cheesebridge who make it their trade to sell the cheese, the White hats like Lord Portly-Rind who eat the cheese, and the Red hats like Snatcher who desire the cheese. But not Trubshaw, he'd rather sit down with a nice jar of jelly. He wants something other than what the majority wants.
- Why did Snatcher choose to use the extermination of the Boxtrolls as his way of obtaining higher social status? A flashback shows that two of them witnessed a crime he committed. So Snatcher was killing two birds with one stone: he found a way to climb the social ladder and a way to discredit and silence potential witnesses at the same time.
- The speech Snatcher starts to make about the "tastiest cheese known to man" is the exact same one he made about the cheddar he had in his lair. Playing white hat was him rehearsing this line, so that it wouldn't be obvious that he doesn't actually know what he's talking about.
Fridge / The Boxtrolls