Having a few thoughts about Umi today!
Mainly, her relationship with her parents, and how it's really good. In the Spring of Eterna, when the apparitions of her parents attack her and Emeraude asks them if their loved ones would ever want to cause them this much pain, Umi can give a definitive no, absolutely not. She has absolutely no doubt that they love her.
In some ways, Umi comes across as spoiled, but it's not an 'affluenza' spoiled. She's lived a life where she's never had to do without, yet it doesn't seem like there was a faulty degree of indulgence. Her parents seem like the kind that would actually take appropriate action to curb the behaviors if they found out she was bullying someone at school and admonish her not to think lesser of people of lower status than her. They've also allowed her to develop her own personality without too much insistence on following norms.
I also feel like Umi would have a low tolerance for bad parenting, just because, "Well, my parents did great with me, of all people, what's your excuse?"