These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Anvilicious - About everything from honesty to sportsmanship to proper piano technique.
Anti-Climax Boss - The final duel between Rob and the main villain is ridiculous and uninteresting. It starts with Vultor kidnapping the moose child at the dam and leaving him on a rock in the middle of ankle-deep watercloseby the heroes and ends with Vultor losing control of his flight in a snowstorm.
Ass Pull - Everywhere. From the Legacy to the lightning powers to the world domination scheme involving chocolate. It's all there.
Canon Sue - Rob. He's destined from before he was born to become a superhero, is always morally righteous, plays sports well, and is a musical prodigy. The people around him constantly talk about how wonderful he is.
Designated Hero - Rob constantly misses opportunities to stop the Jackals throughout the movie, and only directly stops like two of them by the time the movie's over.
Ensemble Darkhorse: Ping, the Garfield-voiced gorilla. Supposedly, besides attempting to make money to rebuild a bar, the characters traveling with Rob believe that they have a "duty to fight against evil," but out of all of them, Ping is the only one who actually does anything against the Jackal antagonists. In fact, he's probably more effective than Rob is, American Rabbit or not.
Ham and Cheese - Kenneth Mars deserves credit for taking this route as Vultor. His performance is possibly the only remotely enjoyable thing about this movie.