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.
YMMV: The Infernal Affairs Trilogy
Moral Event Horizon: Hon Sam in the second film letting his Thai buddies massacre the non-active-gangster members of the Ngai family, including an old woman and a small child.
Nightmare Fuel: Hong Kong is implied to be Hell from the blurbs at the first and ending parts of all three films. Essentially, all of the characters are trapped in this continuous hell and forced to suffer for all eternity.