People change.
When my oldest lass was at primary school, one of the girls in her class started verbally bullying her. We told our lass that if it happened again, she should walk away. If the girl followed her and continued, walk away again. If the girl still followed her, turn around and say, in front of her friends, "If you don't like me that much, why are you following me around ?". The bullying stopped.
A few years later I was at a parent's evening at the secondary school, without my daughter in tow. I got chatting to one of the other girls, who said she really admired my daughter for her ability to get her head down and concentrate on the work when others on the class were being rowdy.
When I told my daughter this, her reaction was "But she was my worst enemy at primary school".