Big Bully in school

Kaitlyn used to chit chat with me before she fall asleep. Last night, she told me that one of her friend likes to roll eyes on her when she meet her in the morning, this little friend likes to "我跟你好，我不跟你好", even don't let her sit in the chair which she have reserve for other friends. Isn't sad if someone don't want to friend with you and treat you so badly. I can understand her feeling but that's childhood. I believe that we all had experience that before also. I told her as long as we treat people nicely, people will treat us the same.