Oldboy/YMMV

Adaptation Displacement: The manga has been all but dwarfed by the film.
Alas, Poor Villain: Right before Woo-jin commits suicide we have a Tear Jerker flashback of when his sister committed suicide. Quentin Tarantino was at the screening and was shocked to find himself crying for a character who had been completely despicable for the prior duration of the movie.
Crowning Moment of Awesome: The hallway fight. Dae-Su fights a whole bunch of henchmen down a hallway with just a hammer and his bare fists. After clashing to exhaustion, with a knife in his back to make things harder, he leaves them gasping for breath and on the floor. He proceeds to the end of the hallway and more of the henchmen appear from the elevator, but he deals with them without breaking another sweat. BADASS.
- For the director as well, given that the entire scene is nearly five minutes long, and is all filmed on one camera, in one take. The fight sequence took three days worth of attempts to nail.
Crowning Moment of Funny: When Oh Dae-Su walk away from the upset woman and the suicide guy falls on the car close by.
- tiktiktiktiktiktiktik PING!
Crowning Music of Awesome: The first movement of Vivaldi's "Four Seasons: Winter" certainly takes the cake, but the entire soundtrack of this movie is a work of genius. Every track is named after a famous movie classic (most of them film noir) yet every title also clearly applies to the events seen in the film when the track is played. Every major character has a theme that is played overtly in several scenes, rather than recurring only as background music. Lee Woo-Jin's theme is lovingly used throughout the film; it is also heard as the jingle marking the release of the gas in Dae-Su's prison and it is the ringtone on the phone given to him by Woo-Jin. The pieces themselves are so appropriate and original that even hearing a few seconds of any part of the soundtrack will instantly conjure up the atmosphere of the movie.
Complete Monster: Lee Woo-jin. And Mr. Park, the warden of the prison.
Esoteric Happy Ending: According to the director, it's either a happy ending that's sad or a sad ending that's happy. Either way, the implication is that the protagonist continues to carry on an incestful relationship with his own unwitting daughter, and that he may or may not know himself.
High Octane Nightmare Fuel: Much of the movie, particularly...well...see above under Gory Discretion Shot.
Karma Houdini: Sure, Lee Woo-jin is dead by the end of the movie, but that doesn't really make up for how very much of an asshole he is throughout the film and how much he gets away with.
Squick: Played first for laughs (like the octopus scene), but getting steadily darker as the film goes on.
Tear Jerker: Several scenes, but especially the unbearable finale when Dae-su screams and grovels before Woo-Jin, begging him not to tell Mi-do that her Dae-su is her father.
- "The Last Waltz", which plays during Mi-do's fantasy of the ant on the train and during the end credits, is a Tear Jerker all of itself, when the movie is over.
The Woobie: Oh Dae-Su. The dude gets locked up alone in a hotel room for fifteen years straight without being told why, and then finds out that he's been manipulated into banging his own daughter. Even the Complete Monster Lee Woo-jin gets a Woobie moment when he watches his sister die.