It's hard to choose.... crying

I guess my favorite would be the episode when Kuuga (vocalist of UxMishi who Sakura likes) corners Misaki near the bathroom, and then Usui appears out of nowhere.

Usui [appears out of nowhere]: "Please do not touch the maids."
Kuuga: "?!!?!? Who the hell are you?"
Usui [while sparkling]: "I'm just a stalker."

I don't remember the lines exactly, so... whee