Pretty Little Liars

Why do people do such stupid things on TV? First having a relationship with your teacher is wrong, and secondly if you are going to have one then don't be so obvious about it.  Why is Aria inappropriately holding her teacher's hand in school with the door wide open?  Anyone could walk by and see them! Errrr, this frustrates me so much, this isn't the way to be discreet...I  mean some has already seen them, you would think that would have taught them a lesson caution.  

And what is up with this A girl? How is able to know everything all the time that the girls are doing? HOW?

I'm tempted to Google who she/he is!