8. Mysterious Pass-out
In order to graduate from the academy, a student must learn basic skills of Ninjutsu, Genjutsu and Taijutsu. Rock Lee had absolutely no skill in Genjutsu and Ninjutsu, even though he was an advanced user of taijutsu. No one ever asked how could he pass knowing just one of the three. Naruto failed just because he didn’t know how to produce a clone at first. I guess we’ll never know how he passed after all. Maybe there’s a special consideration for him.
7. The Wood Release
Wood Release is a Kekkei Genkai of the Senju Clan. However, Hashirama Senju was the only person who could use it. Both Tobirama, and Tsunade had the required natures to use this. However, somehow, no other Senju Clan member was seen using this ability, which is very confusing, and is an unsolved mystery.