The Girl on the Train
The first half of the film is about the delineation of a really sick person -- Emily Blunt's Rachel. She's irrepressibly alcoholic. She has lost everything of meaning to her, and now she's dependent for survival on the kindness of a very tolerant friend. And for something to live for: getting glimpses each day on her train ride ostensibly to and from work, of a couple who live a dream of life of never-dissipating sexual interest in one another and who are absolutely gorgeous to boot. She's the sagging hag, drinking deep her water-containered vodka, while they're redolent of living Adonises from whom even a fountain of youth might draw inspiration from.
The only other version of her that we see is when she reminds herself of her behaviour when drunk while with her husband. She acted out, a lot; she was violent. She damaged other people's lives; cost them their jobs. Her husband evidently couldn't deal with it anymore, and, even though it was with someone he met before his relationship with his wife was over, he still admirably cut his losses and moved on with a life with someone else. His evolving life with her, his new wife, is actually the other thing that Rachel witnesses... actually in their case, more than witnesses: every once in a while she finds herself invading their home and doing the like of wandering out on their lawn with their new-born child.
This story of Rachel is, in short, about exactly what one would show an acting out friend to induce them to perhaps consider AA. You're not glamorous, you're sick. Akin to the very, very sick -- and sad -- that Rachel's ex-husband assesses Rachel as, in an actually kind effort to invite someone else to draw back from assessing her as just a very dangerous psycho.
So the heroic moment from what we've seen of her to this point, is her actually attending a meeting of AA and admitting that she is afraid of herself. She might actually hurt someone; her business with her her ex-husband's baby might have been about something abominable -- the very worst you can imagine. She might also have killed the beautiful young woman of the fantasy pairing, as others, who were actually trying to help her but whom she had in return only abused and accosted, had assumed she had.
But then the movie changes. It turns out she had remembered things wrong. And while it doesn't turn out that when drunk she was actually the life of the party, she was in truth a harmless drunk: all she ever does is quietly pass out. The violence she remembers was actually performed -- often upon her -- by her ex-husband, who is -- unredemiably in his case -- a psycho monster. It turns out that she had been focusing all the blame on herself, that everyone else -- her friends, the police, people she didn't know on the train-- were doing so also, when it belonged upon the story's true monster, who would have her staying feeling terrible about herself to keep his own self intact.
So all that's left for a complete rehabilitation of her self-image is to join his current wife in abolishing him from the planet. This they do, with her doing the initial stabbing, and his new wife deliciously twisting the knife in (if there is anything of their actions that warrants some legitimate self-incrimination, it'll thereby go on the new wife.). She doesn't go back to AA because those truly sad sacks-of-shit, who were nodding the whole time she described the absurdly awful things she did while drunk, had in retrospect taken the bait to reveal themselves as a different level of pathetic. All she needs to do is sit in a different seat on the train... which comes across as making just a minor adjustment, and she's an empowered modern woman with great vistas ahead.
Somehow I suspect that the sequel to this movie will involve her enjoying a terrific sex-life with the hunky psychiatrist in the movie, who while first implicated as a jerk, gets rehabilitated as absolutely beyond-doubt good. And a great plus: He's a darling at not questioning the motives behind women who find themselves with babies they've innocently killed, so surely neither those whose abduction of other people's babies never quite gets cleared in our memory as something that's maybe more on her rather than her most vile of ex-husbands.
Police detective Riley, who's no-bullshit, all-confrontation, will probably getting a passing mention in the sequel, but only to show that those who could still complicate a restored self-image with things like the truth can have miserable things befall them. I suspect we'll find out she'd been the whole time addicted to cocaine. This movie is based on the best-selling book, probably in the world. And just like if a public wants a Trump, there is nothing a sober truth-telling media can do, if it wants a cultural sphere which completely exonerates people like us who might be feeling guilt-befallen, there is nothing an old-style hard-medicine dispenser can do to which won't end up getting turned around so they become the actual problem.