Doctor Strange: Pain's an old friend.
There's a threat made to a character. Maybe it's Cold-Blooded Torture, maybe it's simply not being paid enough, or maybe having their heart broken. They profoundly underreact. Is it because they're zen? Because their mental fortitude is just that great? Are they just nice?
No, they've been through so much terrible shit that they just don't care. In other words, there's nothing you can do to them that life hasn't already outdone in terms of pure misery, so they just blandly accept whatever misfortune that comes their way because nothing could possibly compare to what happened already.
Torture them? Meh, couldn't be worse than their traumatic past. Give them bad food? They've probably eaten worse. Underpay them? They've been through worse. Break their heart? They've felt worse.
See also Conditioned to Accept Horror, in which is not that the person is too broken to react, but that they actually find this normal and mundane. Similar to Insanity Immunity, except in this case the character still holds to their sanity, to Disability Immunity, where the disability in this case is psychological rather than physical, and to Empty Shell and Stopped Caring, with the difference that this character can still feel and care normally. Also, The Last Dance, when the character becomes this moments before his/her unavoidable death.
- The Protagonist of My Youth Romantic Comedy Is Wrong, as I Expected is a young boy who experimented the deception of human relationships at short age, especially about the rejection of girls and ostracism of his class towards him. All of that makes him a lone wolf who doesn't want/interest to make any kind of relationship, sees the youth as a big lie and has a misogynistic vision of women in general (with the exception of his little sister); reasons more than enough for his teacher to force him to be part of the Service Club in order to "save his soul" and "being more human". During the series it's seen how Hachiman commits social suicide acts to achieve his goals for the Service Club, which could left devastated if it's made by anyone else, but he isn't affected a bit... except when he sees the collateral damage he makes to Yukino and Yui everytime he does this in the series, which makes him question his own methods for first time.
- In Naruto there's this image◊ of Obito Uchiha against Kakashi Hatake in which the latter made a hole in Obito's chest and he stands up as if nothing happened to him. This image quickly became a Memetic Mutation, being used by loners about love deceptions as they have no heart to be broken, and having a lot of derivated memes, some funnier (or more depressed) than others.
- Daredevil: Given how much the titular hero suffers in his life, this trope does tend to pop up now and then.
- In the Born Again storyline, Wilson Fisk does everything in his power to make Matt's life living hell, and destroy everything he had. When Matt is left homeless and penniless with barely any of his sanity left, Fisk thinks he has beaten him... Only to realise that he has created a man with nothing to lose, and thus a man without fear.
- This happens again in a later storyline when Mysterio tries to break Daredevil as his dying act, only for him to deliver a scathing "The Reason You Suck" Speech and explain why that's not possible.
Daredevil: You think you can break me? You're a joke and a fraud. [...] And trying to drive me insane? Kingpin nearly did it, once.
- Present in the comic prequel of the game Modern Warfare 2: Ghost. The protagonist, Simon "Ghost" Riley, is captured among other soldiers. Then they are put under torture during months until their will breaks, as the first stage of a long term program of brainwashing. This works with all of them, except for Simon. The reason? His infancy was so ridiculously abusive and traumatic, that the only thing the torture did for him on a psychological level was reawaken those traumatic memories. And as he explains to a thug before killing him, they could not break someone who is already broken.
Simon "Ghost" Riley: There isn't a man alive that doesn't have a breaking point. Your mistake with me was that I'd already reached mine a long time ago. I was already broken, mate.
- In an early 1980s issue of The Incredible Hulk the Hulk is leaping around the world and lands in Afghanistan at a time when, in real life, the Soviet Invasion of Afghanistan was still going on. He drops right in front of an Afghani who barely even notices the Hulk and walks on with the same shocked expression he had had before the Hulk landed. What was going on in his vicinity is so horrific that the arrival of the Hulk doesn't even register.
- In Spider-Man: Noir, Felicia Hardy is the only person alive who knows Spider-Man's secret identity. One mob group tried to get his name out of her through Cold-Blooded Torture. The second mob group took one look at what was under her mask and decided there was nothing they could do to her.
- The Sacred and the Profane: Played for horror and tragedy with Zirah. There's really nothing the other characters can threaten him with, because over the course of his millennia-long existence, the worst has already happened. He's been kicked out of Heaven, gone insane, committed countless evils, and lost all empathy for everyone. He's ultimately undone by the one person he genuinely cares for, and who still cares for him: Caphriel, who is able to get the drop on him and douse him with holy water.
- Played for Laughs in Hot Shots! Part Deux, when the Qurac Torture Technician tries to interrogate Colonel Walters but discovers that his torture has no effect whatsoever. Walters then reveals that he had been married twice, earning a respectful nod from the torturer.
- In Ikiru, Kanji Watanebe has stomach cancer and as a result is expected only to live another six months. He makes getting a children's park built his final project. At one point a Yakuza boss who wanted to build a block of restaurants on the spot where the park was getting built threatens to kill Watanabe; Watanabe just grins after hearing the threat, which completely unnerves the Yakuza boss and his underlings.
- Pirates of the Caribbean: Dead Man's Chest: As Bootstrap Bill helps his son Will escape from the Flying Dutchman, Will points out that the other crewmen will know he did so and will hold him accountable. Bootstrap, having already pledged to serve on the hellish ship for all eternity, merely laughs and says "What more can they do to me?"
- In the original movie, what made Godzilla so hard to kill wasn't his incredible durability but the fact that his mutation into his current form caused him more pain then anything humanity could do to him.
- Discussed in Conspiracy Theory: after Dr. Jonas captures Jerry and (falsely) tells him Alice is dead, a despondent Jerry mutters, "Then you can't hurt me anymore." Jonas's smirking response: "I'll be the judge of that."
- Played with in the dramedy film Into the Night. Jeff Goldblum's character Ed Oken has been suffering from chronic insomnia, apparently for years. During the course of his two-night adventure, he encounters threats, violence and murder, including David Bowie's assassin character sticking the barrel of a Walther PPK in his mouth while interrogating him and, later, the need to try and talk down a surrounded former Iranian secret police agent who has taken Michelle Pfeiffer's character hostage. For the most part Ed barely reacts with anything more than mild bemusement or disbelief (although a jump scare with a barking dog briefly panics him). His condition has left him mostly detached from the reality of the dangers around him.
- The Death Gate Cycle: The Lazar are undead monsters whose souls are fused with their bodies in unimaginable torment. They can shrug off almost anything, even dismemberment, and do because every instant of their existence is far worse.
- In Harry Potter and the Prisoner of Azkaban, this is one factor that allowed Sirius Black to remain sane even while in Azkaban, a prison guarded by joy-sucking Eldritch Abominations. Sirius is so unhappy already, over the deaths of Harry's parents and over his own wrongful imprisonment, that there isn't really much joy left for the Dementors to eat. This in turn is aided by the fact that he is consumed by thoughts of revenge, which fuel him enough to stave off despair, but aren't happy thoughts, so the Dementors can't take them away from him.
- In The Lord of the Rings, Eowyn is able to shrug off the usually crippling despair that follows the ring wraiths. It's not because she's 'just that badass'; it's because she's been living with depression for years and is just used to feeling utterly hopeless and acting in spite of it.
- The Alienist: In the second season finale, after interrogating Libby, Thomas concedes his inability to break her will. Laszlo retorts:
Laszlo: You can't break someone that is already broken, Mr. Byrnes.
- In an episode of Malcolm in the Middle, Francis is taken by a secret society at the Military School to be tortured. When they suspend him, blindfolded, over a "bottomless pit," threaten to flog him to death, and even put his head inside a cage with some hungry rats, Francis responds that he's not scared at all. When the leader asks how their tactics are not scaring him, Francis says that his mom had humiliated him so much, that he had lost the ability to be afraid of anything else.
- In the fifth season of Supernatural, Dean Winchester has returned from hell, where he had taken up torture and kicked off the apocalypse. When one of the Four Horsemen, Famine, arrives, he inspires gluttony in everyone around him. Random people die via cannibalism or alcohol poisoning. Sam drinks Demon blood. Castiel devours red meat. But Dean wants nothing; needs nothing. Dean tries to pass this off as a good thing, but Famine points out it is because Dean is dead inside.
- Dungeons & Dragons: In Ravenloft, many beings are forced to live eternally in ironic hells. Lord Soth actually escaped because he was so broken he accepted his punishment and nothing the dark forces could do hurt him anymore.
- The Warhammer 40,000 games (Dark Heresy, Rogue Trader, Only War and probably Deathwatch) all include an advantage called "Jaded", meant to represent the character having gone through so many of the horrors that are normal to the Crapsack Universe of 40K that the only things that can make him nervous any more are the literal Cosmic Horrors.
- Thaddeus "Rusty" Venture of The Venture Bros. could very well be the Trope Codifier. No matter what horrible things can happen to him in the show, he's been through worse. An abusive childhood has made him incredibly callous, as mentioned in the quote above. When the Monarch tries Cold-Blooded Torture on him, nothing has any effect due to him having experienced almost all of it at some point. Trying to crush his spirt doesn't work either, because he's so depressed and bitter that old college friends of his consider it almost creepy to see him looking happy. The Monarch puts it best:
The Monarch: What can I do to this guy that life hasn't already?
- Gravity Falls: The Society of the Blind Eye try to use their memory wiping machine on crazy Old Man McGucket, but it has no effect on him because "you can't break what's already broken!" It's later revealed that using the machine multiple times to forget the things he's witnessed while working for the Author is what drove him insane in the first place.
- Exploited in the Rugrats episode "Chuckie's First Haircut" where Chuckie is afraid to get his hair cut for fear it'd get hurt, but then the other kids point out that he already feels bad imagining it, so it can't be much worse.
- Steven Universe: Blue Diamond's pathokinesis takes her grief and pushes it onto anyone around her, making even the most resilient Gem break down and sob... except for Lapis Lazuli, who, after spending most of the last 5000 years either imprisoned or in a living hell, is barely fazed by Blue's powers.
Blue Diamond: What?
Lapis: [wipes a single tear from her eye] I've felt worse.