In The Book of Life, at least three of the deceased Sanchezes died by trying some stunts as bullfighters, all believing that "(Insert subject here) are for cowards":
Luis tried fighting three bulls at once because "fighting just one bull is for cowards".
Jorge tried fighting a bull with just one arm and leg because "fighting with two arms and legs is for cowards".
Carmelo fought a bull without using a cape, because "using a cape is for cowards".
In Grave of the Fireflies, the main character, Seita, endures incredible hardships with his sister during and after WWII. Most of that hardship is a result of him running out on his kinda-mean-but-not-that-bad aunt's house to live in a cave. One of the reasons the aunt resents him is that instead of working, he goofed off during the day. And instead of getting a job, he runs off with his toddler sister. Even when things become so bad that their lives are threatened, instead of simply asking his aunt to take them back, he sticks it out, while his sister eats mudballs out of hunger. And then both he and his sister die.
This is a rare justified example, though, because Grave of the Fireflies was originally a novel, and the novel was written by a WWII survivor named Nosaka. Seita is an Author Avatar of Nosaka, and Nosaka was torn up with guilt that in real life, he believes he really did indirectly cause his sister to die of malnutrition.
It's also a case of Values Dissonance, because Seita is now the only man in the family and would be expected to take up the responsibility with this, meaning he should be capable of taking care of himself and is sister and not "crawl back" to gain help from his aunt in the eyes of a Japanese.
Olaf, whose fondest wish is to experience summer, even though he's a snowman. Unlike Anna, however, Olaf has the excuse of basically being a child and genuinely not knowing better.
During the reprise of "For the First Time in Forever," Anna is oblivious to the increasingly violent snowstorm surrounding Elsa. The result is a near-fatal ice blast to the heart.
After being thrown out by Marshmallow, Elsa's giant snow golem of a bouncer, despite Kristoff begging her to leave him alone, Anna throws a snowball at it. Not only does the snowball absolutely no damage whatsoever, Marshmallow becomes so angry that he chases them off a cliff. Fortunately, he had no intention of truly doing them harm and just really wanted them gone (though in earlier drafts he was trying to kill them). In fact, he was already leaving before Anna tossed the snowball.
Pinocchio from Pinocchio (1992) (and every other version) is warned by the Cricket not to go to Dunceland, because his wanting of a life of just fun has caused him many problems in the past. However, Pinocchio goes there and pays it dearly. He almost ends being drowned in the sea as a donkey.
Gene and the other Nicelanders from Wreck-It Ralph have their town in danger of being destroyed, thanks to the eponymous Villain Protagonist, who makes the plot in their world work, leaving them. To clarify, Ralph is a Punch Clock Villain, playing the bad guy in Fix-It Felix, Jr., with the Nicelanders as the NPCs. However, Ralph and Felix are the only ones who even seem aware of the fact that Ralph is the most important asset of the game. Without him, the game literally won't function, which will cause the game to be decommissioned, which will make every resident either dead or homeless. Instead of respecting this, or even trying to be personable to Ralph, the JerkassNicelanders shun him and are generally mean to him, which eventually leads to Ralph leaving the game to try to prove that he can be a good guy. Not only does this mean that Ralph isn't in the game (which, again, is vitally important), but by the time he comes back the game is only a few hours away from being unplugged, and it's too late for his return to make any difference because in the meantime Felix has vanished into Sugar Rush while trying to find Ralph to bring him back. What the Hell, Townspeople? indeed.
Bing Bing, Riley's imaginary friend in Inside Out, misreads a sign above Abstract Thought that reads "DANGER" as "shortcut", despite Sadness warning him that they shouldn't go in there to get to the Train of Thought and should go around the other way. They go in anyways and change into abstract versions of themselves that fall apart. They nearly get stuck in the chamber and get killed until Sadness tells them to fall om their faces to escape. Thanks to this, they wind up missing the train.