Why do girls like to play mind games?

Okay, today at school (in chemistry class), a girl that I know was complaining about 3-4 guys saying that they had sex with her (and that this was false, and I also didn't hear about this until a later period).  I was trying to ask her what she was having and issue with, but she kept on saying that I was none of my business, yet constantly taking to her other friend about it, who was sitting right next to me.  Well, complaining to her friend about the incident 3 times in a row, I would make a comment to her that she just needs to calm down, clear her mind, and focus on her school work.  But after I would say this she would scream at me "MY_NAME_HERE YOU DON'T KNOW WHAT I AM GOING THOUGH!!!!!",  then I would replay "Well, how am I supposed to know what your going through if you won't tell me what is happening,".  This cycle repeated about 5 times within a half hour.

Well /lounge/, what kind of mind games have girls played on you?