Well-Intentioned Extremist/Film

• Angela from Sleepaway Camp sequels is practically the namer for this trope. If you don't believe me, watch the films.
• HAL 9000 in 2001: A Space Odyssey. He is only devoted to the mission at hand, and believes that Dave and Frank will jeopardize the mission by disconnecting HAL after lip-reading from them that they intend to do so if the AE-35 component does not fail as HAL has predicted. It's argued that this could be a paranoid development within HAL's systems, due to his programming disallowing him from lying, whilst he is also keeping hold of a prerecorded message from Dr. Floyd that he is to keep hidden from the rest of the crew.
  • HAL later shows remorse for his actions, leading up to a surprisingly powerful Tear Jerker moment.

HAL: Look Dave, I can see you're really upset about this. I honestly think you ought to sit down calmly, take a stress pill, and think things over. I know I've made some very poor decisions recently, but I can give you my complete assurance that my work will be back to normal. I've still got the greatest enthusiasm and confidence in the mission. And I want to help you.
HAL: I'm afraid. I'm afraid, Dave. Dave, my mind is going. I can feel it. I can feel it. My mind is going. There is no question about it. I can feel it. I can feel it. I can feel it. I'm a... fraid. Good afternoon, gentlemen. I am a HAL 9000 computer. I became operational at the H.A.L. plant in Urbana, Illinois on the 12th of January 1992. My instructor was Mr. Langley, and he taught me to sing a song. If you'd like to hear it I can sing it for you.

• • • However, another theory is that the remorse HAL showed was false, and simply an effort to play on Dave's sympathies so that he could dispatch him later.
• Speaking of AIs gone wild, VIKI of I Robot. She basically imprisons all the humans in her city to protect them from themselves.
• Poison Ivy in Batman and Robin (though she does make her extremist ways known from the outset), as well as the version of the character from Batman: The Animated Series. In fact, most of the animated Bat-villains are sympathetic in their first appearance, then less so as their motivation shifts to "revenge on Batman".
  • A similar thing happened with the version from The Batman, who was set up as even more sympathetic due to being a teenager, but, in subsequent appearances, becomes simply a villain. Subverted in the show's spin-off comic "The Batman Strikes", in which her sympathetic aspects and good intentions are retained.
• The Operative in Serenity is very extremist but still fits in this category. He attempts to paint himself as Necessarily Evil, however.

I'm not going to live there. There's no place for me there...any more than there is for you. Malcolm...I'm a monster. What I do is evil. I have no illusions about it, but it must be done.

• The Paladins from Jumper hunt and slay members of the titular breed of humanity to protect the world from the Jumpers' sociopathy that descends into evil. This would be a reasonable claim if not for the Paladins' killing of the Jumpers' friends and family too.
  • The paladins' stated reason has nothing to do with the above. They claimed that Jumpers were evil based solely on the fact that "only God should have the power to be all places at all times."
• Jigsaw in the Saw movies claims that his sadistic deathtraps give people an opportunity to truly appreciate what they have by making them fight for it. That the survivors are left emotionally traumatized and usually horrifically mutilated seems to be merely an unfortunate side effect.
• The Galactic Empire from Star Wars: most generally believe that they are the good guys fighting rebel "Terrorists".
  • Not to mention Count Dooku...for a while, anyway.
    • Word of God (from Lucas and Christopher Lee himself) says that Dooku never quite realized how evil he had become, and, right to the very end, honestly believed that he was doing the right thing. The Expanded Universe has different interpretations of his motivation, though, and even the novelization of Revenge of the Sith turns him into a power-hungry racist; this is especially strange because no other source depicts him that way.
  • In the Expanded Universe, this is often made the Sith's hat. Some writers portray the Jedi/Sith rivalry as less of a Good versus Evil conflict, and more of an Order Versus Chaos, or stagnant repressive government versus anarchy and freedom, dichotomy.
• Hot Fuzz: The Neighborhood Watch Alliance of Sandford have been killing off anyone who may lower their chances at getting the "Best Neighborhood" award. Not well-intentioned enough? It's because one of the protagonists' mother committed suicide after the neighborhood didn't win once. One of the villains is the mother's husband and, thereby, said protagonist's father. He always knew that he's his father though, so this is not an example of I Am Your Father.

"If mum knew what you were doing she'd kill herself again!"

• Brigadier General Francis X. Hummel just wants to get pensions for war widows in The Rock.
• D-FENS from the film Falling Down.
• Father maintains a forced regimen of the anti-emotion drug Prozium on the populace in Equilibrium, ostensibly to avoid future global conflicts like the one that drove them into semi-seclusion. Mildly subverted in the end when Father DuPont, lamenting the imminent downfall of his society, admits to Preston that he (Father) does not take Prozium, and thereby is a hypocrite.
• Gerard Butler's character in the drama/thriller Law Abiding Citizen is a textbook example of this. He's a man who saw his wife and daughter murdered by thugs and then watched one of the thugs get off lightly due to a dubious plea deal. This gives him a right to be pissed. And if he had simply botched the execution of one to result in a very painful death and murdered the other, he might manage to be simply an Anti-Hero and still remain sympathetic. On the other hand, murdering every single person connected to the trial in some way with an extraordinarily executed Batman Gambit, and threatening and targeting even their families may be seen as going a little too far.
• Death Wish is one of the Most Triumphant Examples of this trope, with Charles Bronson killing any thugs who menace others... granted, they have a terminal case of Too Dumb to Live going after Bronson, but still.
• In The Boondock Saints, the brothers' crusade against evil could be described as a mild form of this trope.
  • Il Duce, on the other hand, plays this straight.
• Christof in The Truman Show sees the real world as a place of pain and misery, so he traps his adopted son Truman in a fake world where everyone he knows is an actor, so that he won't have to face reality.
• Jet Li's character in Warlords started out as a straight hero until the half way mark, when he had to decide how to provision his limited supply of food. He had enough to feed his army for 10 days, but if he shared it with the army that had just surrendered to him, there wouldn't have been enough food for anyone to live. His solution: massacre the enemy army. He remained well intentioned and acted in the interests of the greater good, but his methods remained unsavory.
• In Final Fantasy the Spirits Within, General Hein just wants to kill the phantoms to save people from being killed by them. Unfortunately, his way of doing so involves killing a bunch more people instead of finding a solution to the problem from the roots, as the Heroine is trying to do, and actively tries to stop them. Yet, still, he is not an outright villain. He has a literal What Have I Done moment.
• In Category 6, when Mega Corp Lexer ignores Dan London's repeated warnings that their power grids are woefully underprotected, he tries to make an example by covertly hacking their mainframe. Unfortunately, a freak chain of events causes this simple What the Hell, Hero? to cause the city's entire power supply to be cut off.
• Ex-Secretary of Education and former 3rd Street Elementary School principal Phillium Bennedict's reason for wanting to eliminate Summer Vacation and, initially, get rid of Recess, as well as to change the orbit of the moon during Lunar Perogee to essentially freeze the planet, was to increase the learning rate and test scores of the nation, as he felt that recess and summer vacation were causing them to atrophy, especially when Canada, Iceland, and Norway had higher test scores than them. Suffice to say, this extremism cost him both his job as principal and the Secretary of Education.
• King Koopa in Super Mario Bros, although a dictator who often subjected criminals to De-evolution, had focused on trying to conquer the regular dimension specifically for his species' survival, and it's really hard to blame him when his current dimension is basically a Crapsack World. It also, in a way, humanizes him compared to his second in command, Lena, who really simply wanted to simply rule everything, not caring whether her race benefitted or not.
• Battra (Mothra's Evil Twin of sorts) in the film Godzilla VS Mothra: Battle For The Earth. On the one hand, he's just doing what he was created to do (IE: Maintain balance between man and nature), but he thinks that the only way to keep nature safe is to utterly destroy humanity.
• Seven Days To Noon: Professor Willingdon wants the British government to stop the production of nuclear weapons and will set one off in central London if they do not comply.
• The Secret of Kells has Abbot Cellach. He acts like a total Jerkass and is completely obsessed with building his wall, to the point where he disdains and eventually forbids his monks from doing anything else. However, the point of the wall is to keep out the Vikings, who already killed all the family he had except for his young, impressionable nephew, who now wants to do non-wall related things like go outside and create beautiful holy books. He doesn't listen when Aidan tells him that his wall won't hold and they should all flee instead, which leads to the deaths of many, many innocent people.
• Sentinel Prime in Transformers: Dark of the Moon, who is willing to join with the Decepticons and enslave the human race in order to rebuild Cybertron. He does go to very dark lenths, even for this trope, however, and different views emerge very fast. Several have accused him of really being an old bastard with a god complex, who did a Face Heel Turn just to stay on a winning side.
• John Travolta's character in Swordfish claims to be this and has no qualms about going after civilians to achieve his goals.
• Loki from Thor can be called this. His actions are ultimately for the good of Asgard, but he goes just a bit too far.
  • Very much so: basically everything he does from the middle of the movie on are to show that he's worthy of his father's trust and every bit the equal of Thor.
  • And he goes even further in The Avengers. He thinks the humans must be enslaved in order to bring peace to them, and he doesn't mind to build his empire on thousands of corpses.
• Also, Thanos in Avengers: Infinity War. This version of Thanos is the sole survivor of a race that destroyed itself due to an overpopulation crisis, and believes that is he removes half of the universe's intelligent life, he'll be saving the other half from wars, environmental degradation, starvation, and more that will lead to even more deaths and infinitely worse suffering.