@makube
Hehe... at least let me spam my thoughts about the matter
Rin's lack of sexual propriety is almost pathological, considering that normal 10-year old girls with normal crushes don't shove their naked crotches up the face of their teachers
BTW, Anna O. wasn't immature, per se. Her deeply repressed sexual urges (I would rather prefer her deeply missing her father) had an effect on her well-being, eventually affecting her body as well. Breuer was the target for her affections, and Breuer's reaction (once he knew that repressed sexual urges were behind Anna's symptoms) was to push her away. Kind of cold, but professional.
Rin, on the other hand, is a physically immature girl who's well-being is affected by the absence of her father (or at least someone who'll stand as her father). Unlike Anna, though, Rin's "come-ons" to Aoki may not indicate a repressed sexual urge, but more likely to gain the affections of her target father-figure. If Anna's target was Breuer, Rin's target is Aoki. Aoki, unlike Breuer, didn't drop Rin like a hot potato... he's trying to walk the fine line between being a professional and being a human being.
That's the point of comparison between Anna O. and Rin, as well as Aoki and Breuer..