Toshiro Hitsugaya: Kuchiki, go that way. Kuchiki, come with me.
Rukia Kuchiki: Can't you just call us my our first names?!
Byakuya Kuchiki: ...
Toshiro: No. Cmon, Kuchiki.
Insight: Toshiro's the type of character whose smaller than everyone else and therefore feels more grown up when he acts like it. He's actually a 150 year old ghost with the body of a 10 year old.
I can't think of any more, but there are so many in Bleach.