I like her too. For one thing, as even Harry acknowledges, she's great for some comic relief. But she's also got a past that's been difficult and she gets picked on and teased a lot and probably overlooked, even by her classmates in Ravenclaw. I reckon there'll be surprises from her in the next book though, like she might figure out the whereabouts of a horcrux or something (if Harry tells her about them).