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.
Big Lipped Alligator Moment: The scene in the book where Minny and Celia are attacked by a naked man at Celia's house doesn't have any real relevance to the rest of the story and is pretty weird to boot. Presumably it was included to show to that Celia is tougher than she looks and can fight for herself, but it's jarring all the same.
Actually, in adds more than you think. It's not there to show that Celia is tough, but to show how far she's fallen in her isolation.
Critical Dissonance: Somewhat. Most reviews of the film were only moderately positive but audiences went nuts for it, hyping it up to be a flawless, must-see movie.
Some of the maid's stories about their kinder employers
Esoteric Happy Ending: The book is published and the maids' stories are out. But Aibileen is now an unemployed black woman in the pre-Civil Rights Deep South whose made enemies with the local white Alpha Bitch. Doesn't seem like things have improved much.
Fridge Brilliance: Celia was able to carry a child after Minny starts teaching her to cook. Prior to that, she was probably subsisting on Coca-Cola and alcohol based on what we see of her habits, not an environment conducive to pregnancy.
During a background moment in the movie, Mae Mobley answers her mother by saying "Yes, Ma'am" (the same way the maids reply to her). Elizabeth has no qualms about this.
That's not as alarming as it sounds — in the South, though much less so nowadays, children do call their parents "Sir" and "Ma'am" out of respect.
Given we know that the KKK is active in the town, Hilly need only have a discreet word with the right people and most of the sympathetic characters are going to develop bad cases of burnt-out homes and gunshot.
Maybe not. Hilly strikes me as someone so oblivious to her own racism—recall her comment "There are real racists in this town!"—that she might be genuinely horrified at the idea of lynchings and burnings, yet have no problem demanding that blacks use different facilities from herself.
Even if Hilly did try to sic the KKK or somebody on them, she would run the risk of them revealing that she was the one who ate that pie as detailed in the book, which she is not going to let happen. That's why Minnie insisted it be put in there.