why do guys like to make you scream...........

why do guys like to make you scream because they like to mess with your feelings and when they do that they think that they can do any thing that they want like flirting with you and then dating someone else while flirting like crazy with you and then right when you think he is going to make a move to ask you out he tells someone who knows you that he has a girlfriend scence april 22nd of this year and you have a big fued with that person and they act like they do not give a crap about you any more. What are we suppose to think when the've been messing with our emotions like that?