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: Aarfy. Among the novel's nastier characters, Milo really can't be defined by human morality and Colonel Cathcart is so over-the-top he becomes funny. This guy has no excuse. He's a serial rapist who kept one of his victims locked up in a closet for an hour before just murdering her outright, and enjoys bragging about his, ahem, "conquests". When a loophole in military policy allows him to pull a Karma Houdini, Yossarian realizes that the United States Air Force really is corrupt beyond redemption.
Cult Classic: The movie, which was not well received in its day.
Fridge Brilliance: The novel may seem to make no sense, but when one thinks about it, that's probably deliberate. Heller wanted to show the nonsensicalness of war.
Milo Minderbinder is the dark example. He starts out as a simple mess officer, is able to construct a black market empire with the help of the US military so he can deliver cheap but excellent food to USAAF messes. He becomes so adept at the world market that he is awarded high ranking positions around the world due to the profits he was creating. He gains so much power that he makes deals with almost every nation (including the Germans—but not the Russians, since they're communist), and it culminates with him accepting a contract from the Nazis to bomb his own base.He gets away with it scot-free.
Orr is the positive example. In spite of appearing as the worst pilot on base, who crashes every single plane he flies, it's ultimately revealed that he was just practicing for his master plan of faking his own death to escape the Air Force and survive the war. Only Yossarian figures it out eventually, and he's left breathless.
Moral Event Horizon: Several, many of them by the United States military, but the most notable happens with Aarfy's rape and murder of Michaela, which is then ignored by the police.
Milo Minderbinder crosses it by trading the squadron's parachutes and replacing them with IOUs.
And his refusal to help Yossarian find the Kid Sister because he wants to buy some illegal tobacco.
The Woobie: Major Major Major Major and, at some points, Yossarian. Also the Chaplain — poor worrywart.