Now that I understand that the entire volleyball segment is a parody of the Attack No. 1 anime (
http://www.dannychoo.com/detail/mac/...hilarious.html) it makes it even funnier. The part where Konata says "are you really Japanese" is probably referring to the line "The tears are coming, she's a girl" which is a from the theme song of Attack No. 1 which I guess was really popular, thus causing her to chide Kagami for not knowing it.