Credit to Dtemplar for a particular line. Credit to Mizura who just enlightened me on why the Uchihas were wiped out by Itachi. They specialized in katons. Itachi topped them by simply learning genjutsu. They'd never thought about using genjutsu even though they were elite Katon specialists. In the past, katons actually had the ability to kill people so this was all well and good, but as villages started producing bigger and better shinobi, the katon fell behind to the point that Itachi got disgusted. I mean we all know that as soon as you know the name of the opponent, kunais and katons become useless He realized he needed a new technique. He asked his father about genjutsus and Fugaku was like "Huh? What's a genjutsu?" Itachi's hate and disgust for the clan deepened at this point. The Akatsuki leader came along and told him what a genjutsu was. Unfortunately, due to his environment, couldn't comprehend what this was. Itachi even threw dirt in his eyes thinking that's what Leader meant when he said you can use your eyes to project the impression of a doton into the opponents mind. Akatsuki leader got fed up trying to explain and told Itachi to activate his sharingan and copy the move he was about to perform. Itachi did as he was told and became the first Uchiha to learn something useful He used his one genjutsu to confound the clan and kill them off while the fools were still stuck with their measly katons. Unfotunately, that dirt that the retarded Itachi threw into his eyes had a bug living in it that caused a progressive eye infection that slowly decays your eyes. Itachi decided he needed a new jutsu and like the 'tard he is figured out a new katon...(the amaterasu in case you were wondering) When he went excitedly to show off his new jutsu to the Akatsuki leader, he shook his head in disgust at Itachi and as punishment, made him wear purple nail polish and partnered him with Kisame(he had the choice of shark freak or venus fly-trap freak and he chose the more human and strangely attractive Kisame ) Later on, the other members thought it was some kind of promotion that Itachi got to wear purple nail polish and started whining at to the Leader who couldn't be assed to explain that he was punishing Itachi and let them all wear it instead. At this point, Oro got extremely pissed off because Leader had forced Itachi to wear Walmart purple and Oro only used L'Oreal products. They had a vote and Itachi's Walmart brand won over Oro's L'Oreal. The only other person that had voted for L'Oreal was Sasori.(They stayed close even after Oro left the group as a result of that night) You see, Oro had always thought that his popularity was the strongest in Akatsuki but it turned out that night that it was Itachi, who had those funky grooves under his eyes naturally who had the strongest popularity rating and Oro was crushed. Oro had to leave and that is why Oro said Itachi was stronger than him.