The reason the ninjas all wear protective headbands is because Naruto originally wore goggles (first episode), but the artist of the manga thought it took too long to draw the goggles, so he replaced them with the forehead protector.
Gaara of the Desert:
Shut up... or I'll kill you.
In some episodes of the series, some symbols on the clothes that the characters wear have some mistakes on them. Like sometimes, the Leaf symbol on the Leaf headbands would not have the pointy part of the symbol on it, and sometimes, the Sound symbol would have either a wavy flag or a non-wavy flag on it. And the Mist symbols would sometimes be lines instead of squiggly lines. On one of the early episodes, Sasuke Uchiha had a blue shirt with the Uchiha Clan symbol on the back, but on one shot where he talks to Sakura Haruno, the Clan symbol is not on his back. And some of the characters' faces were drawn badly in the original Japanese film, but were edited in the English version.
In the Japanese version of the anime series, after Naruto does the Sexy Jutsu (in both the first and second episodes) there is blood coming out of either Iruka, The Third Hokage, or Ebisu's nose. In the English release of the anime, this was completely altered to make it appear that the characters were falling backwards (something that happens frequently in anime when an unexpected event occurs). But for some reason, in the episode 2 dub, after the 3rd Hokage "falls backwards", he gets back up, and there is a trace of blood on the handkerchief under his nose, suggesting that he was only bleeding a little bit.
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