The fact that Haku will probably have to remind people all his life that he's a guy and that Kimimaro has become a Nightmare Fuel Station Attendant. Also this exchange in Wave Country:
Naruto: "...it's always fun to hang around there and gamble."
Neji: "Only because you're the one who always wins without cheating."
Naruto: "Neji. I know that you're a light enough sleeper to hear me. If you kick me one more time, I'm going to bite you."
Neji: *Kicks Sasuke instead*
Sasuke: "I hate all of you."
In the Kaguya District, the kids try to be as stealthy as possible opening a door. Neji and Hinata look for switches, Sai makes mice to find latches, Haku and Gaara use their various elements to try and pry it open... And then Naruto loudly punches it open by accident.Don't say it indeed.
Someone falls into the traps Hakumei set up around Tazuna's house in Wave. Gaara reports on what happened, starting with the man falling into the foul-smelling....something that Naruto filled a pit with, to facing a barrage of senbon set up by Haku, to then running straight into a patch of hallucinogenic mushrooms.
Haku: Was he really bad? Gaara: He ran up thinking I was a buxom blonde woman of about twenty-something. Then he decided that I was his...mother.... Haku didn't know what to say to that.
Chouji vs. Kin during the Chuunin Exams:
Chouji: (only casually dodging a hail of senbon) Whew! It's a good thing I stayed still... Kin: Fatty, if I wanted to hit you, it wouldn't be that hard... (Stunned Silence) Chouji: Who are you calling fat?! I'm big-boned! YAY FOR BIG-BONED PEOPLE! Kin: A dinosaur is big-boned, Chunky! You just have a blubber problem! Shikimaru: (quietly) ...doomed.
Zabuza: "I'm going to kill him." Haku: "That would start a war." Zabuza: "But it will make me feel so much better..."
Shortly after finding them and giving them baths, Tsunade and Shizune cut the kids' hair. Sakura and Hinata take it very well, Neji, Haku and Kimimaro end up not getting their hair cut, and Naruto, Sasuke, Gaara and Sai try (and fail) to keep Tsunade from doing it.