[quote=Kaga]
Except the weirdest part is that, despite this argument, she still show her teeth... sort of. But, like, only the top row. Really it just looks like she's raising her upper lip. So I don't even know why she's presenting such an argument as if that's the problem here, which it's not. @_@
[/quote]

Then my best guess would be that she's bluffing (consciously or not) and there's something else at play.
That, or maybe the top lip raising like her smiling is unconscious and she doesn't realize she's doing it.