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.
Complete Monster: Gordon Northcott is a serial kidnapper, abuser, and murderer of as many as 20 young boys. And the movie left out a lot of details about his real life crimes.
Crowning Moment of Awesome: Or rather, a crowning third act of justice as Northcott is captured and sentenced to death, and the police force is disgraced in court by Collins' attorney, S.S. Hahn.
Hahn himself counts as a crowning character of awesome. The film's first two acts are difficult to watch due to the blatant injustice that Collins suffers, but then she is released from the institution and the third act is a powerhouse of justice against the police force led by Hahn. It's an incredibly satisfying conclusion, remarkably so given that the film ends with Christine still without her son.
Nightmare Fuel: Sanford's confession to the police makes the one from Se7en look like a church book club discussion.
Paranoia Fuel: The police can replace your missing child with a random runaway, convince everybody in your neighborhood that your protests as to his real identity are not just wrong, but signs of abuse from you, and eventually throw you into a mental institution without a warrant just to shut you up. And this really happened.