A girl was left by her best friend when she moved to Canada. She was comforted by her friend who was leaving– they agreed that would talk on the phone every day and nothing would change. When the girl called her friend a week after she had left, everything had changed. There was no longer that best friend connection. That bond that had existed over the last 3 years was no more. It had vanished instantly it seemed.
This sort of thing happens all the time, it just seems that people are a much less aware when it happens slowly. Not until looking around and being startled by the emptiness does it really hit people.