why is it that when your friends come to you for advice and you give it to them, and they dont take it....

my friend often comes to me and asks for my advice, mostly with relationship stuff, and when i give it to her she says "your right" then does the opposite. then comes back and says she should have listened to me. once or twice ok fine but she constantly does it over and over again. and she keeps getting hurt and gets stressed out and then comes to me again.......