I also hate her personality too until I read her background story. DAMN! I mean, with what happened to her at such a young age, I would also become her just minus for being a math genius
SPOILER
We also had a glimps of her background in the manga of her being beaten by her uncle but that's not the worst part yet. It'll be very very worst and it resulted to her not being able to know, recognize things and to talk.
(The manga didn't explained it yet but the MC cannot recognize and distinguish appearances so she measured every crook and cranny of a person's face and that's the reason she'll be able to know who she's speaking with, like how she able to pin point the prince was outside by the length of his bangs to his height)
I hate her personality, I hate that the braided hair b*tch is using her, I hate how she can't even defend herself, I hate how she can't NO, and I HATEEEEEEEE THE PRINCE!!!