Really quiet useless girls, there's no specific example because they are everywhere but they annoy the crap out of me. The same goes for boys, I suppose. Characters that have zero self esteem are just annoying - mainly when they come from a decent background or have no real issues. I can handle a character like Shinji because there's genuine reason for him to act like he does and because of it, it doesn't annoy me.
So... characters that are incredibly feeble. I hate.
So... characters that are incredibly feeble. I hate.