A peaceful Night

Hello, my friends.
  It is Monday now, and most of us has work later therefore they are tuning in early now. Even so, i do not have work or school later hence i am able to not sleep too early. Hmm, is it weird to address you all as friends even though we never even met? How do everyone define friends? Must it be people you have to meet in person? Can the meeting be only once in a lifetime, and you can consider that person as a friend? For me, Friends is those people who does not harm me, Harm as in little potential threat. They may sometime be unwilling to help you in some things but i don't think because of that reason you can break friendship. What do you all think about this? Who is friend? And what does a friend really need to do? Do you guys feel that friends are the most important things in your life?
  There have been instances where friends who were a backstabber, but for some strange reasons you are still friends with people like that. I had a friend who could not keep her mouth shut about stuff which led to some consequences that could have ended really badly, but after that incident we are still best of friends. Strange isn't it?
  In this peaceful night, i am thinking of such a queer question. What about enemies then? How to define enemies?