Deidara’s obsession for his art is perhaps his most notable personality trait. He seems to view each and every bomb he creates as a piece of art and a significant accomplishment in its own right. He left his home village of Iwagakure, because they disapproved of the techniques he developed. He hated Itachi for defeating his art, and even developed C4 clay and trained his left eye to counter genjutsu for the purpose of defeating Itachi someday. Deidara even once exclaimed to Sasuke in their fight that Sasuke had no respect for his art and that it made Deidara want to kill him. He even seems to value his art more than he does himself, wanting to fight Naruto with only one arm because he viewed him as, “the perfect canvas for my art” and even knowingly killing himself in one massive explosion to kill Sasuke. Considering the nature of his technique involves large explosions, it can be argued that Deidara is a big attention seeker. Before he joined Akatsuki he worked as a terrorist bomber for hire and travelled all over the world bombing different places. Also when he was brought back to life by Kabuto, he was visibly angry to learn that his final explosion didn’t get that much notoriety and refused to acknowledge that Sasuke survived the ordeal. It is clear from how little Deidara valued his own life when it came to his art, that it was the source of his self-worth. After all it was perfect in his eyes and by extension made him perfect for creating it. Though there is one hole in this theory and that would be the partnership he had with Sasori. Deidara seemed to openly acknowledge that Sasori was more powerful, and even referred to him as Master Sasori out of respect for him as a fellow artist. Yet Sasori didn’t respect Deidara’s art and called it little more than a cheap “pyrotechnics display”. They even bickered frequently about whose beliefs on art are accurate. So why was Deidara so tolerant of Sasori’s disrespect of his art when it made him want to kill others? Well Sasori believed art was meant to be eternal , and last forever. Sasori also gave up his human form to be a living puppet, which made him immortal. Deidara may have looked at this with admiration as Sasori sacrificed everything to be one with his art, though Deidara had not. Then again perhaps Deidara respected Sasori for the opposite reason, that he cared so much about preserving himself. Sasori developed his living puppet body and his puppet body armor Hiruko for the purpose of protecting himself, whereas Deidara’s art can easily do harm to himself and more often than not has. Since Deidara doesn’t value himself and only his art, this different set of ideas Sasori had may have made him want to change and value himself. Deidara was also the one that usually egged on Sasori in their arguments. He may have wanted the fights so Sasori could convince him otherwise. Of course Sasori’s death confirmed in Deidara’s mind that Sasori had been wrong all along. Though he still regarded it as a death worthy of an artist. Anyways these are just my thoughts on what made Deidara the way he was.