So, let's get serious: despite having Amano as the alleged narrator, this is really Gasai's show.
We as the audience are left asking, <what's up with her?> It's not immediately clear if she's crazy in a real way, or just in whatever way is convenient for the plot.
But in the end, it all makes sense, and that's great.
People praise _Bakemonogatari_ for its interrogation of the Tsundere stereotype and what it would take to make a person behave like that. _The Future Diary_ does something similar for the Yandere.