Methinks yandere doesn't mean what some people seem to think it means...
Ikwym a yandere is someone whose emotions switch from lovey-dovey to murderously ultraviolent, someone criminally insane and extremely dangerous, but lately I see lots of commenters who throw around the word 'yandere' as soon as a character reveals she has a just slightly crazy and obsessive side.
A good rule of thumb should be: if things haven't gotten to the point where you wanna see that character locked in the Elizabeth Arkham Asylum for the Criminally Insane, then don't call her a yandere.