Why do you think shes so much more angry at her father than her mother, even though they both made her work.

Melinda makes the observation that her father's job is far less taxing than her mother's. Her dad talks on the phone and goes out to lunch.... his days seem to be easygoing, whereas, Melinda's mother works hard and faces possible layoffs. We also see that when she went to work with mom, Melinda was able to sit back and read.... with dad, she worked the entire time.