Rachel indeed learned the hard way, which somehow suits her because I know a simple pep talk wouldn't have an effect on her former mean attitude. Her self-centered attitude was really annoying, and I'm glad her mom didn't tolerate that. It's a good thing that she chose to accept her mistake and make amends with her friends, despite the fact that they had also caused her harm.
You are right. Sometimes learning the hard way is the most effective. It's great that Rachel chose to make amends and grow from her experiences.