It opens your chest and it opens up your heart and it means, sumone can get inside you and mess you up..... You build up all those defenses ; you build up a whole new suit of armour, so that nothing can hurt you. Then one stupid person, no different frm any other stupid person wanders into your stupid life. You give them a piece of you.They did not ask for it.They did sumthing Dumb one day like smile at you or kiss you or maybe even an innocent hug....and suddenly your Life isn't your's anymore ! DamN.