Family, community, and belonging
The boy is an orphan, implying some kind of familial story. The story is about an orphan "finding a family" so to speak, trying to belong in a community that rejects him. This issue of belonging ends up dictating the nature of the climax, because Hugo escapes the Inspector by running into the arms of a magician, Georges in disguise. Georges will be Hugo's new family.
Hurting the ones who need help
Instead of recognizing that Hugo is an abused orphan and deciding to help him, most of the adults just care about how the boy makes them feel: stressed, tired, and annoyed. He is stressful to the adults because he represents a reality that is hard for them to face: They should help him. So, Hugo ends up being mistreated by many of the authorities and adults who work at the train station. Even Georges doesn't like him. Eventually, Hugo works through this with Georges by his side, but originally, Georges found him extremely obnoxious and troublesome.
Destiny
When Hugo ends up fixing the toy, it is the key necklace of his young friend Isabelle that helps him operate it for the first time. It plays his father's favorite movie, and then they learn that Georges's signature appears at the end. He must have a secret life. The secret ends up being that, in addition to being a skilled toymaker, Méliès is also a skilled filmmaker, thought to be dead. In the end, he ends up being Hugo's caretaker, and they watch movies together. The fact that Hugo's random friend and random toy were connected and the fact that they were connected by a person with a significant story of his own, both point to destiny. The two characters were destined to help each other back on their feet.
