When Friend Become Enemy

Do you ever have this kind of situation? When your friend suddenly become your enemy for some reasons? Some people says that there is a very think line between friend and enemy. So when there is something happen that can trigger the emotion of those two people, they can brake this line. And what it happen to you, what will you do? Are you a person who want to keep a long lasting friendship or you just simply forget the person and try to find another friend? I think this question can be simply to answer but can also be so difficult!

WHAT WILL YOU DO?

ps. just in case somebody read about this...