We finally see that yes, her tantrums are of a spoiled brat, but in the end, she searched for Marinette. It was always about her and HER opinions. The bullying, everything, was all for her. The reaction she never got from her mother, the attention she always wanted, came everytime from Marinette and she enjoyed that in a twisted way because she had control of someone.
And when Marinette rejected her, in Chloé's last attempt to get any reaction from Mari, she broke. She finally broke because she was truly alone. And i liked that. Indifference is worse than hatred.
Chloé lost the last person in her world, and that was Marinette.