The titular protagonist of Naruto is the perfect example of a flawed character, but one of his biggest flaws is largely due to the influence Kurama has over him. Naruto is rambunctious and explosive and has a huge knack for mischief and pulling pranks. Although he has come a long way from his mischief-filled beginnings, there's no doubt that this is a core trait of his character, seeing how it was a prank that threw off the series' final villain and gave Naruto and his allies the upper hand. While Naruto might have been blamed for this rash nature, the fault really lies with Kurama.
The day that Naruto was born, Kurama, the nine-tailed fox, attacked the Hidden Leaf Village. The Fourth Hokage saved the village by sealing Kurama into Naruto at the cost of his life. Naruto grew up hated by his village because they saw him as the demon fox in child form, something the Naruto pilot originally canonized. This led Naruto to start pulling pranks across the village in order to get attention.
Naruto having to resort to pranks really is Kurama's fault on the surface, but it goes deeper when one considers that Naruto choosing this as his outlet is also due to Kurama's influence, based on the way foxes are viewed in Japanese culture. In myth, foxes are worshipped as trickster spirits that engage in mischief and bewitchment. They'll play tricks on samurai, monks, commoners, etc. and these tricks can range from harmless to excessively malevolent. Foxes are also viewed as servants of Inari, the deity of rice. Many shrines dedicated to the kami are adorned with fox statues offering protection. There is also a children's game involving foxes that is similar to rock-paper-scissors, or the three-way deadlock closely associated with the Sannin.
Knowing this, it's now clear why Naruto was the prankster he was in his early years. His attitude is definitely his own, but Kurama's presence helped manifest Naruto's outbursts. Ultimately, this ends up being beneficial to Naruto, as he's outsmarted and outwitted countless opponents. Naruto and Sasuke tricked Zabuza with a demon wind shuriken, Naruto tricked Pain into letting him gather Sage chakra, and the aforementioned final villain was tricked by nothing else other than Naruto's signature Sexy Jutsu.
What started out as Naruto's biggest flaw has become one of his most effective tactics, and it's all thanks to Kurama. Foxes are tricksters in Japanese myth, and Kishimoto took this idea and made it a quality of his protagonist. Without Kurama, Naruto very well could have ended up like many other shonen protagonists, but the influence of the fox makes Naruto and his unruly mischief unique.