Why would a girl treat you mean for no reason? & treat everyone else nice?

I'm in a weird situation, i was dating a girl and we broke up. then all of a sudden poof, this girl that has been in my life for a few years has struck my attention. kind of like the person you never noticed and one day you look up and instantly have feelings for them. she has ALWAYS given me the... Show More

whenever I start ignoring her or giving her the cold shoulder, that is when she starts to open up and be nicer. than back to ice queen. that's why she got an ultimatum this time.i was a tad harsh but not mean. I guess we'll see. like I said baffles me.