Yes I like her. But if I don't like her, I would still ask this question if someone treated me like she did (the part when she ignored me like a complete stranger). Obviously I wouldn't go on other websites asking if that person likes me if I don't like her back, but the question posted here would still be posted. Most of the cues that she gave me that might signify she likes me, I actually omitted them here but talked about them on other forums, because I came here not to talk about how likely she likes me. Most of the other cues, like looking my way at certain times for instance, well I can easily imagine that happening even if she doesn't like me, so there's nothing odd or unexplainable about them either way.
But to answer your question of why I care (even if I don't like her): It's usually pretty easy to tell if someone is a likes you or dislikes you (as a person, not romantically). However, If he or she treats you like you're a total stranger for a good period of time (even though that person clearly knows you), then all of a sudden start being nice to you, well I guess I'm just curious as to why he or she doesn't seem as straightforward as most others I met. In fact, the way she treated me, I can easily imagining something like this happening in the workplace, where office politics means that I'll meet many who aren't as straightforward as they would be in college and it might seem good to understand such people right now if I have the chance. Though admittedly, I guess I did learn from the replies here that humans can be irrational, and I shouldn't care about it as much as I have.
I should also say that I'm pretty socially awkward, and pretty much "broke out of my shell" so to speak only when college started. So I always feel like I need to learn more about humans interact. even if at times I shouldn't care that much.