When I believe something must stay in its rightful place, exactly as it is, for me to be OK, I have become attached to it, I have confused this external thing with who I am. If that external thing changes, and eventually everything does, how do I react? If I have placed my sense of self in it, then I have to defend it. I have to argue for it. I have to come up with definitions, and meaning. In short, I have created an attachment.
