I've got this one easy.
Cecile Lafitte from Gosick. This woman is one of Kujo's (pictured left) teachers. And boy, is she annoying. You know what she told Kujo on his first day at the academy? To "make 100 friends and climb the Alps, Kujo-kun!" With a squee here and an immature rant there, this adult teacher acts more childishly than Victorique (another character in the show). And she just pops out of nowhere everywhere.
This character tends to make my blood boil. I wish she would be spirited away by the demon. (Haha, Higurashi reference!) Cecile makes me take on this sort of expression/feeling/mood:
You know who Cecile can be compared to?
Yeah, I went there.
Tomorrow's prompt: "favorite anime couple"