The Villain is a Well-Intentioned Extremist and really does have standards and adheres to them religiously, even though he does other horrifyingly evil things in the name of his cause.
The villain commits his misdeeds to get rich, so he gets angry when another villain threatens to destroy the world. After all, there's point in having illicit money if you don't have anywhere to spend it.
Inverted: A hero has a line of things too good for him to consider doing.
Some things are just not evil enough for the villain.
Subverted: Somebody suggests killing a relative of the witness to a murder. The Mob Boss says "No.", and, much later, when asked, proceeds to explain the Pragmatic Villainy reasons for not doing so.
Double Subverted: Somebody suggests killing a relative of the witness to a murder. The Mob Boss says "No.", and, much later, when asked, proceeds to explain the Pragmatic Villainy reasons for not doing so. And then mentions that "Even if all that weren't true, it just isn't the proper thing to do."
Parodied: The bad guy has a "Evil Etiquette" book, and the Complete Monster is scolded by other villains.
The bad guy has no problem with mass-murder, but draws the line at emailscams.
The murdering arsonist absolutely refuses to jaywalk.
Deconstructed: Implication and consequence of extremely amoral acts are shown, to the point that a pragmatic evil code is provided.
Zig Zagged: Somebody suggests killing a relative of the witness to a murder. The Mob Boss says "No.", and, much later, when asked, proceeds to explain the Pragmatic Villainy reasons for not doing so. And then mentions that "Even if all that weren't true, it just isn't the proper thing to do." And then the guy dies anyway, and everyone thinks it was him, but then he finds and turns in the real killer, who was the guy he talked to. Mob Boss gave the order to kill as a Xanatos Gambit: Whether the witness dies or not, the Mob Boss has an excuse to punish the guy for an unrelated offense, but with the witness' death is not the prefered outcome because they had kids to support.
Averted: The Mob Boss doesn't even consider turning on the Complete Monster.
Alternatively: Nothing too heinous ever comes up.
Enforced: "We want him to be more of an Anti-Villain, so we need to give him a code of honor and a moral line he will not cross."
Lampshaded: "Don't fear, Bad Guy will not kill you. It would be too evil".
Invoked: "As main witness of Bad Guy crime, I suggest you to get pregnant, fast."
Defied: When somebody suggests the Mob Boss should turn a Complete Monster into the police, the Mob Boss refuses, pointing out the monster is still good at what he does.
Discussed: "We're not dealing with some kind of comic book supervillain here. People, even if they're criminals, aren't going to immediately throw all moral standards out of the window."
Conversed: "I heard this movie has some interesting antagonists. Some of the villains are actually shocked when the main bad guy commits particularly heinous acts, and refuse to help the main bad guy any further afterwards. You should go see it!"
Look, I may be a murderer, but I'm not gonna leave a troper in the lurch: here's a link back to Even Evil Has Standards.
