If a Character Flaw is introduced in fiction, there are only a few conclusions it can reach: it's something to overcome, it becomes quirky and cartoonishly exaggerated, or it completely takes over their motivation or sanity. This trope is the last one.
This trope is in effect when a work treats anger, hatred, and other negative emotions as being a lifestyle, which one either follows or does not. In Real Life, people are complex things which can feel a variety of emotions and motivations, all at the same time, and often overlapping in undetectable ways. For example, a loving father who wants to protect his daughter may also hate all of the various forces that can harm her. A bigot may hate a particular group, but otherwise have innocent, tragic, sympathetic or even noble qualities about them. Granted, even in Real Life, personal faults fuel subconscious behavior, but in fiction, the proportion is greatly exaggerated.
This trope is where negative emotion or Angst is no longer functional or conducive to whatever passes for a "normal" life in the work. Rather than channeling their negative emotions into constructive pursuits or having a mere Moment of Weakness, a character flat out gives in to "The Dark Side" (or, said moment is treated as a sin too terrible to be justified or forgiven). A father who doesn't just want to protect his daughter, but control every facet of her life and will disown her if she disobeys. A Spirited Competitor who doesn't just hate to lose, but so averse to losing that they become a Blood Knight or The Berserker. A crimefighter who isn't just out to avenge their murdered loved one, but forego any kind of normal life or personal feelings unless they can be used to further their crusade.
What makes this "Straw Angst" is that, as we said, everyone feels complicated emotions and sometimes what we think are positive emotions can be intertwined with negative ones. A Kindhearted Cat Lover may be lonely inside and only feel love from their feline friends. Someone greatly fulfilled by The Four Loves may actually be terrified of being alone (because Loners Are Freaks) and feel their worth is tied to the love of others. A desire to help people or fight For Great Justice may come from someone who truly loathes crime and injustice in any form. But as we said, "Straw" Angst needs to have these flaws "resolve" somehow.
A Shadow Archetype usually embodies these emotions, as they represent emotions, feelings and traits that a person tries to deny. A God of Evil or substance Made of Evil may also embody it and/or induce it. See also the Seven Deadly Sins.
A person of Incorruptible Pure Pureness or a Purity Sue would be on the extreme far opposite as someone whom the story claims has no angst or negative emotions. For this type of person, loving all people and animals has no deeper need and fighting crime and injustice has no angst or trauma to fuel it—it's just what they do. On the other end, see Ambiguous Innocence, where a character has no negative emotions or angst, but this means they also lack restraint, fear, or an aversion for doing horrible things accidentally or for fun.
Good Is Impotent plays with this trope, as it acknowledges that moral "goodness" can't get anything done without negative feelings, but still creates a dichotomy that separates the two into "good" and "evil".
Deconstructions of this trope usually include Happiness Is Mandatory, Getting Smilies Painted on Your Soul, Crapsaccharine World, and The Complainer Is Always Wrong, where negative emotions are suppressed or outright forbidden.
- Always Chaotic Evil: A society with no nuance or moral complexity to it—they are evil, and they are committed to evil in every way possible, including feeling and/or spreading negative emotions. Typically used to contrast and oppose a society that is Always Lawful Good, which shuns such emotions or feelings.
- As Long as There is Evil: Until humanity is absolutely perfect and does no wrong, this threatening thing will keep coming back.
- The Dark Side: Where there is a codified morality and some sort of "force" that feeds from the negative side.
- Drunk on the Dark Side: When a person becomes addicted to their negative or dark emotions.
- Emotion Eater: Negative emotions fuel the villains and make them more powerful.
- Freak Out: The exact moment when the negative feelings take over, and the person can no longer be normal or functional.
- The Heartless: Negative emotions in monster form.
- If You Kill Him, You Will Be Just Like Him: An argument that a person who commits murder (no matter how justified) is as bad as the person they murdered.
- Jumping Off the Slippery Slope: When a person who was able to be functional or rational despite negative feelings completely abandons it to pursue them.
- Passion Is Evil: Caring a lot about anything is bad and will make you a bad person.
- The Power of Hate: When hatred toward someone or something gives you strength or ability.
- Revenge Before Reason: When a person needs to avenge themselves or others no matter how much damage it causes.
- Straw Nihilist: A character who finds no meaning in life decides to destory all of it rather than, say, make one themself.
- Then Let Me Be Evil: Often a result of this trope; if everyone else thinks your negative quirks make you a monster, then why not be a monster?
- There Are Two Kinds of People in the World: Usually, a more "positive" character will tell the angsty character this, implying that the latter is one of the "bad" people.
- With Us or Against Us: Can be said either by the angsty character to demonstrate that they don't care about anything but their obsession, or the "positive" character to indicate that their angst is unwelcome.
Examples which do not fit any of the subtropes above:
- Kirby's Dream Land 3: The villains Dark Matter, and later his core Zero, are stated to be incapable of feeling positive emotions, and declare that, if they can't do that, no one else should.