you don't know people.
Sometimes things are superficially happy, and you can run around and put shaving cream on the mirrors with someone and laugh hysterically seven times in a day, and think, damn, I've got it good.
And then, the next day that same person will say something so utterly shocking, or insulting or wrong, so that, even if for a brief moment of time, you'll say in your mind, I can't believe I ever thought I knew you. Sometimes I told you things that I wanted never to be repeated, and I thought, you're on my side. Obviously, I was mistaken.
It invokes this horrible feeling in your stomach, betrayal.
When you know your best friend is coming home, and you can't look her in the eye, that knowledge of even indirect loss of confidence sits in your stomach worse than jealousy.
It's scary to realize how easily someone you've known all your life can suddenly become your sworn enemy, both of you permenantly stuck in a cycle of misunderstanding.
This, it seems, is a fear no one can deny having. That one day, you'll wake up, and find that everyone you once knew, everyone you'll ever see and interact with, love and hate and care for, has become a total stranger.