life

I'm reading a book about intimacy. It says we see ourselves the way people define us. If people say we are good then we believe we have to be. Lazy, happy, slutty, smart, whatever the opinion we believe it and try to be it. I may be just stating the obvious but it's interesting to think about. All these characteristics are parts people see on different occasions. Probably all of us are something different at some point in life. The book says we only know who we really are if we are alone and go inside of ourselves. But aren't we defined by the way we interact with the world around us? Who are we when we are totally alone?