What do you think of this girl?

I use to like this girl who was very mysterious and rude with me. I know that her sister and brother have a bad relationship, they curse and insult one another and probably more. She probably does the same.. Not publicly because shes a shy person, but shes probably just as bad as them. Her mom is also a person whose bad, she even ignored my mom in person. Our families both know each other. Now back to the girl I liked. She use to just hide and ignore me when we were in person, I just tried being nice to her I never did any harm to her! Then she talks to me in facebook and acts all flirt and interested. Then in person she just hides. Its like this... She just walks around me ignoring me, Hoping I'll talk to her , and then she just runs off. Man she just likes to piss me off, she is around me and yet Doesn't show any affection for me. She just wants me to engage with her and she pulls away. It also happens online, I ask her something she responds and when i try to continue she breaks off leaving me hanging. Likewise it happens in real life. Why the hell is she like this? What do you think of this person?