Aunt Petunia made Harry cook for them, Uncle Vernon trash-talked his parents, and Dudley regularly intimidated him and treated him like a burden.

Source: https://www.cbr.com/harry-potter-hated-disliked-characters/

Her physical appearance is described as "horse-like" and "ordinary," something Petunia desperately wanted to be.

Source: https://www.cbr.com/harry-potter-characters-who-aged-poorly/

While Petunia shrieked at Lily's magical abilities, she longingly asked her sister how she managed to do it.

Source: https://gamerant.com/harry-potter-lily-petunia-evans-relationship-explained/

You may recall Petunia getting a howler from Dumbledore that said: “Remember my last.”

Source: https://www.buzzfeed.com/hanifahrahman/harry-potter-tv-storylines