A character is or becomes complacent after an extended period of nothing bad happening. They begin or already do believe that nothing bad could happen. Or if they do, perhaps they're too apathetic to actually do anything about it.
But then, events conspire to affect them in a certain way. They would make sure the character goes through a rude awakening, wise up, and get their act together. Depending on how they respond, it can result in Character Development.
One of the few things that can get someone with their head in the sand to wise up before it's too late.
Compare We Have Become Complacent, which is this trope applied on a society-wide level, Back in the Saddle where someone rejoins a dangerous profession and has to relearn the dangers involved, and The Call Knows Where You Live if the protagonist believes current events won't affect them until they do.
- A few from Assassination Classroom:
- Terasaka was the last of the Class 3-E students to come around and be a better student. The trigger event was when he realised he was manipulated into endangering his classmates. After helping save their lives, he becomes a better student and person.
- Karma likewise gets this after the mid-term exams. His classmates studied hard both to ace the exams and win their bet with the elite of the school. But he relied too much on his natural talent to think he even needed to study. However the end result proved otherwise as he doesn't even make it into the top ten of the scoring. Kuro-Sensei chides him for it and tells him just because he has talent, that's no excuse to stop honing it, especially when his other classmates are doing their best to better themselves from their flaws. Karma takes it to heart and becomes more active with the other E-Class students going forward.
- In Darwin's Game, Minoru refused to accept Kaname's help, refused to understand the true danger of their mutual enemies, believing their fighting force to be superior. It was not until Kaname demonstrated the superiority of his modern weaponry compared to Minoru's village's weapons which were Iron Age at latest did he realise how badly in the wrong he was.
- In Is It Wrong to Try to Pick Up Girls in a Dungeon?, Bete told Lefiya straight to her face that he considers her The Load and added that their friends being too nice and forgiving about Lefiya's The Load status was detrimental to her development as an adventurer. Lefiya admitted he was right and started taking more active steps in becoming stronger rather than simply lamenting her weakness.
- In One Piece, Luffy and his crew's journey through the Grand Line ocean isn't exactly a leisure trip, but they pulled through everything it threw at them up until the Sabaody Archipelago arc (and, for Luffy, the Marineford arc), which is the first time they met a "brick wall". The Marine Admirals are way out of their league, and despite his best efforts and many hits he took throughout, Luffy is ultimately unable to save his brother, Ace, from execution, unlike in other arcs. After the Marineford arc, and learning just how tough the journey ahead is going to be, Luffy decided that he has to get stronger if he wants to stand a chance in the "New World" (the other half of Grand Line), and tells his crewmates (in his own subtle way) to train themselves for it.
- In Nana to Kaoru, Kaoru calls out Nana's teacher and classmates for taking advantage of Nana and pushing their work onto her. He demands to know what they'll do once Nana inevitably graduates and they can no longer rely on her. The outburst made them realise how much stress they were placing on Nana to meet everyone's expectations. Kaoru's outburst was so potent that the next day, they were tripping over themselves to apologise to Nana for how much they took advantage of her without thinking about how much stress they were heaping on her and give a promise that they'll step up and actually take their own initiative.
- In The Rising of the Shield Hero, the other three summoned heroes besides Naofumi were less than great at their jobs, often causing as much if not more trouble than they solve due to their belief it was all just a game. It was not until after the Spirit Turtle incident, where they suffered personal losses and their reputations became tarnished due to them being the cause of it did they realise that the world they're in is not a game and that their actions have very real consequences.
- In Yu Yu Hakusho, up till meeting Toguro, Yusuke manage to pull through his cases fairly well with a bit of luck and ingenuity with his powers. However after Toguro shows that he took a dive in their first encounter, reveals that Yusuke, along with Kuwabara, Kurama and Hiei, have been invited to join the Dark Tournament and refusing would be a very bad idea via a demonstration of his strength by utterly totaling the parking lot they're talking in with just a fraction of his power. Yusuke realizes that this matter is extremely serious and willingly goes back to Genkai, fully intent to put his all into his training this time to boost his power so that he can survive what's to come.
- In Pokémon Reset Bloodlines, Giselle got this twice over. Firstly, she and her classmates received a huge dose of Humble Pie that forces her to learn that her academic accomplishments are one thing while practical experience and the ability to think outside the box is another thing entirely. Secondly, she realised what horrible jerks she and her classmates were to Joe after he tells her straight up that he hated their teaching methods which did not thing but caused him to resent their school.
- In Pokemon: The Origin of Species, Laura spent years putting her Intrepid Reporter career on hold, and forgot about the dangers involved up until she was given a huge reminder when police rocked up and confronted her and took her equipment. She later admits she needed that for her old training and experience to kick in after years of being left unused.
- The Lion King (1994): Wrecked with guilt over his father's death, not helped by Scar's manipulations, Simba fled from the Pride Lands and his responsibilities, growing up under Timon and Pumba in as carefree an environment as possible. But when not around Timon and Pumba, it's clear that Simba is still wrecked by his guilt. It wasn't until Nala, Rafiki and the ghost of his father talking to him in succession did he get over his guilt enough to head back to face his responsibilities.
- In Sing, Meena's grandfather put his foot down on Meena's Performance Anxiety and Stage Fright and tells her to try again and do it with full confidence. It was what Meena needed to hear to overcome her problems and it worked a lot better than her mother's reassurances.
- In Animorphs: The Ellimist Chronicles, unambitious gamer Toomin is deeply shocked when he discovers his neighbor Lackofa has been selected for a position aboard Ket's first manned deep space expedition. Having previously been content to waste time repeatedly losing the same game, he takes this as a "wake-up memm" indicating that he should start taking his life seriously. And then the Capasins arrive and start wiping out the Ketrans, prompting Toomin to assume leadership of the survivors - beginning his centuries-long transformation into the Ellimist we know and love.
- In Guards! Guards!, Vimes started out as a drunkard and the rest of the (very small) City Watch was no better. Then Carrot joined the watch, the dragon was summoned by a conspiracy, and these two factors together succeeded in making Vimes, Nobbs and Colon get their act together and save the day.
- Judge Dee: In The Chinese Maze Murders, a Brilliant, but Lazy painter has been happily sitting on his laurels by creating lurid imagery for Taoist monasteries rather than the elegant landscapes the Confucian administrators prefer, and having an extraordinarily high alcohol tolerance gives him a very good reason to enjoy renting an apartment above a wineshop. But after the girl he fell in love with is murdered, he decides to make something of himself in memory of her, including moving into a house... which the wineshop owner takes as a personal insult.
The painter had become a changed man. He had foresworn drinking, a decision which involved him in a bitter quarrel with his landlord, the owner of the Eternal Spring wineshop. The latter took this decision as a reflection on the quality of his stock. All winebibbers of that quarter sadly called this breach the end of a beautiful friendship.
- Eddie Guerrero got his wake up call on the very first Ring of Honor show where he failed to defeat IWA Puerto Rico Intercontinental Champion Super Crazy. This was Guerrero's second loss since his five year return to the independent circuit but his first of that year and his last had been against Low Ki, an unfamiliar opponent and the top champion of Impact Championship Wrestling. Super Crazy however had been lower on the card than Guerrero back in AAA, which caused him to question if the younger wrestlers were getting better or if he had simply lost a step. Eddie would be more successful in subsequent ROH matches teaming alongside The Amazing Red and even squashed Brian XL in a singles match.
- In Ensemble Stars!, the events of Love Comedy serve as this for Kaoru - he entered Yumenosaki only intending on lazing around and flirting with girls, as he saw this as his last chance to live for himself before he'd be expected to take on the family business. However, over time he slowly comes to realise that he does enjoy being an idol and has made some really close friends there. So when, a couple of months away from graduation, Rei shows him a newspaper article reporting a scandalous photo of him out with a girl (which is very bad for an aspiring idol), he realises he can't put it off any more and will need to decide very soon what he wants from his future.
- In Final Fantasy X, every member of the party who believed in the Final Summoning got one at Zanarkand. The Final Summoning has no chance of defeating Sin permanently. It was all a lie. This revelation put the final nail in the coffin of whatever faith they had in Yevon left. After defeating Yunalesca, they set about finding a way to truly defeat Sin permanently.
- In The Legend of Zelda: Breath of the Wild, due to being bitter about her inability to awaken her power and jealous of Link who's fulfilling his part of their shared destiny, Zelda lashed out at him, up to and including claiming she doesn't need him as her bodyguard. When she get ambushed by Yiga Clan assassins and Link saves her, she realised how wrong she was to take out her frustrations on him and she does need him to protect her.
- In Volume 1 of RWBY, after an argument with Weiss and a lecture from Ozpin, Ruby learns that since she's the leader of her team, she needs to actually act the part. She can't goof off all the time, she has to step up and be a proper leader even when not in battle or on a mission.
- In one arc in El Goonish Shive, Grace and Adrian Raven had the best of intentions when they wanted to prevent a wild boar from being killed. They thought that there was a better way of dealing with the situation. They were forced to learn that good intentions means zilch if poorly thought out when they were forced to kill it themselves to prevent Grace from getting hurt and were forced to admit that there was no other realistic outcome.
- The Order of the Stick:
- Xykon got comfortable after conquering Azure City, but the IFCC wanted to push him out of his comfort zone, so they made a deal with Vaarsuvius hoping the elf would (and did) confront Xykon. With the phylactery going missing, the effort succeeded.
- Redcloak got two in fairly quick succession. The first was from Xykon during his own Wake-Up Call above, and the second was after a resurrected Jirix passed on a phrase from their god The Dark One.
- In one episode of Avatar: The Last Airbender, Aang got comfortable on Kyoshi Island due to his fanbase, forgetting about the war that he as the avatar was supposed to stop. And then the Fire Nation attacked, giving Aang the reminder of his responsibilities he needed.
- In Steven Universe: The Movie, Steven has gotten comfortable with his Happily Ever After and doesn't want anything to change. Then Spinel comes crashing in threatening to take that happy ending away, forcing him to jump back into the fight and save the world again while learning An Aesop about change.