Often, an anime will include characters whose personalities are characterized by maturity and seriousness. However, this does not mean they always live up to their poised and mature reputations. Often, the climactic moments of the show push these characters to break their constancy.

RELATED: 10 Times An Immature Anime Character Acted Maturely

Whether it be because they are unnerved by the enemy, made to feel vulnerable by a friend, or stressed by the intensity of the plot, these characters break their typical mature demeanor and do something that can only be described as immature. Despite their otherwise calm and logical exterior, some characters are prone to fits of immaturity.

10 Naruto's Sakura Haruno Likes To Think She Is Mature Until It Comes To Sasuke

Sakura is mid-jutsu

When Naruto returns to the Hidden Leaf Village after training with Jiraiya for years, he and Sakura team up to go find Sasuke at Orochimaru's lair. They are forced to take with them Captain Yamato and a new teammate, Sai. Sai is rude at first and often insults Sasuke, which makes both Naruto and Sakura angry.

However, Tsunade entrusted the usually mature Sakura with ensuring that Naruto was on his best behavior. Unfortunately, it is Sakura who ends up being the one to give Sai a knuckle sandwich for his insults.

9 Light Yagami Is Very Mature Until He Lets The Power Of The Death Note Corrupt Him

Light Yagami is expressionless

Light Yagami is regarded as a genius. He was logical and level-headed, and he knew it. However, when he got the Death Note, he slowly became corrupted, and with that corruption came a level of immaturity.

Eventually, in a quest to become a sort of god on earth, he got too cocky, and his immaturity cost him his freedom. Among the immature things Light (aka Kira) did was killing those who loved him, underestimating his enemies, and letting the power go to his head.

8 Todoroki Is Calm, Cool, & Collected, But His Father Can Get To Him In My Hero Academia

Todoroki uses both quirks

Shoto Todoroki is one of the top students at U.A. His Quirk is powerful, and his handle over that Quirk is extremely impressive. Even so, there are moments in the anime where even Todoroki can't handle the heat, and this is largely because of the abuse doled out to him and the rest of his family by his father and the Number Two (now Number One) Pro Hero, Endeavor.

RELATED: 10 Coolest Anime Schools, Ranked

Todoroki has a hard time reconciling his fire abilities and not wanting to be like his father, and sometimes, the pressure boils over and he snaps, not unlike how he acted at the sports festival.

7 Avatar: The Last Airbender's Katara Is The Mother Of The Group, But Even She Lashes Out

Katara lets Southern Raider go

Katara is generally seen as the mother of Team Avatar, and she took on this role before the group ever met, since her mother was killed by the Fire Nation and she had to assume a lot of maternal responsibilities at an early age. She is often the one having to talk sense into the other characters and make them stay on track.

However, this does not mean she is always the mature one. There are plenty of times where she is jealous of Aang for his natural bending gifts and gets angry with him, and there are certainly times where the pressure boils over and she lashes out, but that is to be expected with a kid who was forced to grow up too soon.

6 Neji From Naruto Is A Mature Shinobi, But His Fight With Hinata Was Out Of Touch

Neji Hyuga stands before a house and stares out in Naruto.

Neji Hyuga is quiet, a shinobi prodigy, and a brilliant fighter. However, he is not always the paragon of maturity. In fact, he almost killed his cousin, Hinata, because of his vendetta toward her father and the Hyuga clan's main family.

While his rage is justified, the Hyuga use of the curse mark is draconian, but taking it out on his kind and gentle younger cousin was uncalled for. There are not many moments where Neji steps out of his usually level-headed, mature persona, but this was definitely one of them.

5 Jotaro Kujo Is Immature When It Comes To His Treatment Of Women In Stardust Crusaders

Birds-eye view of Jotaro in Diamond is Unbreakable

Jotaro Kujo is without a doubt a brilliant tactician and a skilled Stand user with plenty of raw talent. However, he is also widely infamous for his treatment of women. From insulting them for little reason to calling his mother curse words, he is notorious for being a bad boy, and not always in a cool and mature way.

Even by the next series, Diamond Is Unbreakable, he has yet to completely shake off his immature misogynistic tendencies, and fans hope to see Jotaro do better in the future.

4 My Hero Academia's Nighteye Does Not Have His Usual Demeanor When It Comes To All Might

Nighteye adjusts his glasses

Nighteye is not the person one would expect to be fangirling over pro heroes, but his love of All Might runs deep.

When Midoriya takes an apprenticeship under Nighteye, he learns that while the Pro Hero and former sidekick to All Might may seem cold and mature to the point of ridiculousness, he is also a lover of humor and a serious All Might fan, sometimes even cracking his mature façade. Still, Nighteye is a serious hero, and his mature persona has most people fooled.

3 In Naruto, Kakashi Is The Cool Teacher, But His Love Of Romance Novels Is Awkward

Kakashi looks worried and ponders

Kakashi Hatake is the mask-wearing cool guy of the Hidden Leaf Village. On plenty of occasions, Might Guy remarks on how he wishes he could be as cool as Kakashi, and Kakashi's sheer power and calm demeanor make him a force to be reckoned with on the battlefield.

RELATED: 10 Anime Heroes Who Look Cooler Older (& 10 Who Look Worse)

However, Kakashi also has a weak spot. That weak spot is "Make-Out Paradise," a romance novel series written by none other than the Toad Sage and Legendary Sannin, Jiraiya. While this hobby does not invalidate Kakashi's cool factor, it certainly provides some much-needed comic relief.

2 Tenzin, From Legend Of Korra, Is Mature But Sometimes Too Harsh

Tenzin cheers for Korra

Tenzin is Avatar Korra's airbending master and Avatar Aang's son. His goal is to guide and prepare Korra while also rebuilding Air Nomad society and restoring their culture. However, one thing Tenzin has a hard time letting go of is control, something that is a bit poetic for an Air Nomad that is supposed to be detached from such things.

Sometimes, Tenzin can let his anger get the best of him and he explodes or makes up unfair rules, but he is human, and one can't blame him for the occasional mistake.

1 Fairy Tail's Gray Fullbuster Is Mature, Until Natsu Gets Him Going

Gray frowning

Gray Fullbuster is usually level-headed and does not like to rush into things, unlike his comrade, Natsu Dragneel, but two things are sure to chip at that mature façade. The first is his tendency to subconsciously take his clothes off, which can make for some pretty awkward situations, and the second is his friendly rivalry with Natsu.

The two have been known to throw down and start a fight in the most inopportune of situations, creating an enormous ruckus, but they are too immature to care.

 NEXT: 10 Shounen Anime With The Most Meaningful Lessons