Well, a good part of the reason why Dawn's acting the way she is is because, at least when they came up with the idea of Dawn, she was supposed to be roughly twelve; but had only been human for one and a half years. You know, in a different rendition of this, she could be Buffy's adopted stepsister and it'd fit almost exactly, and like particularly stepsiblings, there's a lot of them rubbing up off oneanother in occasionally fighting ways, occasionally covering for eachother ways. But still, I have to admit that I love the pairing- especially as siblings!