Found this Long-Neglected YKTTW of mine. Has a good number of examples, so will launch it tomorrow if there are no objections.
Laconic Definition: Out-of-Character justified in-story.
No protagonist is perfect. Every man or woman brings their own unique flaws and difficulties to their role in a story. Often stories will be about a protagonist's struggles to overcome these flaws. However, whether they succeed or fail, many of them will experience at least one Moment of Weakness. That instant in which their emotions or the stress of a situation goes past critical and causes a thoughtless reaction that they would never
have if they were thinking clearly.
A Moment of Weakness can come and go, but will usually be recognized very quickly by the perpertrating protagonist. The typical response is usually one of two extremes. Either they'll wonder with horror "My God, What Have I Done?
?" or it will be the first step
in a running jump off the slippery slope
. On occasion you can even get someone who realizes the horror of their action but not have that be enough to stop the leap.
To mitigate the potentially subjective nature of this trope: A Moment of Weakness is a single moment in which a character's emotions or stress levels run so high that they act contrary to their usual nature. This action almost always causes damage of some kind, most commonly to someone the protagonist cares about.
See My God, What Have I Done?
for more long-term examples and Start of Darkness
when the Moment of Weakness sends them the other way.
Anime & Manga
- Saki's Kunihiro Hajime gave in to the urge to use sleight of hand to win a Mahjong tournament in grade school. Even into high school this act haunts her, undermining her confidence to play without doing so. This is the reason she's Chained by Fashion.
- Daisuke Suwa found himself falling for the Bitter Virgin Hinako Aikawa. But when she obliviously gives him a Just Friends line, he angrily blurts out that he knows her dark secrets. He gets lucky that Hinako wasn't actually listening to him at that moment but is horribly ashamed of himself afterward.
- Ling in Fullmetal Alchemist knowingly makes a Deal with the Devil and allows himself to become the new Greed because of his obsession with gaining immortality. Possibly a subversion, as a factor in Ling's decision was he would have died otherwise and Greed later did a Heel-Face Turn, suggesting that it ultimately wasn't a bad decision.
- During the Water Seven arc of One Piece, while having a heated argument with Usopp, Luffy blurted out that if Usopp didn't like the way he did things then he should just leave the crew. Sanji immediately stepped in to shut Luffy up, and Luffy apologized as soon as he realized what he'd said. But the damage had been done, Usopp took Luffy at his word, and (temporarily) left the crew.
- In Star Wars Episode II: Attack of the Clones, Anakin Skywalker was perfectly content to sneak around the Sand Peoples' camp and not start a fight up until his mother died in his arms. His rage at that moment prompted him to murder every Sand Person there. He felt guilt over it afterward, but it didn't stop his fall to the Dark Side. It only got worse from there.
- In The Dresden Files book White Night Harry is forced to acknowledge the steadily growing influence of Lash after he loses his cool and destroys part of a building with his magic. Something the nature of Dresden-verse magic would make impossible unless Harry really believed in what he was doing. One of the book's villains, the Skavis, specialized in provoking and manipulating Moments of Weakness to make his victims commit suicide.
- In the Pendragon series Bobby pushes a bad guy out of a helicopter. The Big Bad had wanted him to do it and told him to and he knew it would end up making things worse but he was really mad and wanted to hurt the bad guy.
- In the Vorkosigan Saga novel Memory Miles covers up an assignment that was horribly botched because of health problems which he had also been keeping from his superiors. Although he's always breaking rules, up to this point it had been for the greater good; this time it was mostly selfish and he is dismissed from imperial service as a result. Later in the novel, when considering the villain, Miles notes that this could have been the point at which he did a Face-Heel Turn, but unlike the villain, he stopped himself.
- In Harry Potter and the Deathly Hallows, it's revealed that it was exactly such a mistake that caused Severus Snape to forever destroy his friendship with the one person he cared for.
- The short-lived television series G Vs E generally had villains who convinced people to make a Deal with the Devil, and good guys getting them to break those deals at the cost of what they were given. One episode stands out, however, as the bad guy of the episode approached people on the verge of death from accidents and used these deals to save their lives.
- Depending on how you interpret Varsuuvius of Order Of The Stick, his decision to make a Deal with the Devil (and Demon, and Daemon) was a Moment Of Weakness. He knew that dealing with infernals was a bad idea, and they even offered an alternate method, which would, however, require him to admit that he couldn't handle things on his own. And so, in a Moment of Weakness, Varsuuvius finds that he cannot admit defeat, and makes the deal, taking a step towards the Dark Side.
- Carl Fredricksen in Up suffers two of these. The first at the beginning of the film. In a panic over his mailbox being knocked over, he hits a construction worker with his cane, getting him branded a public menace. The second is near the climax when the Big Bad threatens to set fire to his house. He drops everything else, including protecting the MacGuffin bird, to put the fire out and snaps at Dug and Russel when Russel calls him out.