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.
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 a video game starring 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 a vital part 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 the villain 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.