* FridgeLogic: At the Bar Mitzvah, Jill feels uncomfortable asking for a glass of milk after eating her secret peanut butter sandwich. Kosher tradition forbids dairy and meat to be consumed in the same meal, and because rare roast beef is part of the menu, milk would not have been available, anyway. The Bar Mitzvah chapters serve only to explain the overall traditions of the event itself, such as the Torah being read in Hebrew; telling Jill the reasons behind the dietary practices is unnecessary for a secular young adult novel.
* MoralEventHorizon: Good God, the things the kids do to Linda for cheap laughs are just outright horrible!
* OnceOriginalNowCommon: There have been constant books, TV shows, and movies made about the nature of bullying, especially among preteen and teenage girls, since 1974. As such, it's easy to write off ''Blubber'' as trite and the behavior of its characters as not that bad. But when Blume first published the novel, it was groundbreaking--''no one'' had written a story that subverted the ChildrenAreInnocent trope. ''Blubber'' was even protested and banned because of the vicious, unrelenting bullies in the story. In short, Blume [[NotHyperbole literally wrote the book]] on this type of character.
* ValuesResonance: This was written in TheSeventies. Its strong message about how devastating school bullying can be and how bystanders who witness it contribute to it even if they don't actively take part make it still ring true even decades later.
* TheWoobie: Linda. In fairness, Linda's experience [[spoiler: doesn't stop her from taking a complete role-reversal with Jill, as Wendy's sidekick in tormenting her. The closing pages suggest that this didn't last, but there's a bit of apparent HobbesWasRight about her behaviour.]]
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