Okay, let's start with the good.
Whatever her other faults (and there are plenty), Dame Olga adores her daughters. She introduces them as "my treasures" (3.17) and addresses letters to "My sweet darlings" (12.15). She tells them not to overexert themselves at finishing school, reassuring them that "If you can sing and dance charmingly, eat daintily, and sew a little, you will be fine ladies and I shall be proud of you" (12.20).
Well, if you set low expectations you won't be disappointed, right?
In looking out for her daughters, Dame Olga makes sure they are properly outfitted with trunks and trunks of clothing. Even when her hopes for Hattie marrying Char fail because Char uncovers Ella, Dame Olga quickly adjusts and tells Hattie to stop protesting: "Don't you want to be stepsister to the queen and make her give you whatever you like?" (29.45). Because clearly, having money and royal connections is the best way to take care of your children.
Dame Olga is not the perfect picture of innocent youth. In fact, she sounds pretty unappealing. She's "a tall, plump lady with long and wavy honey-colored tresses. Her face was a pasty white with twin spots of rouge on the cheeks" (3.12). Her voice is "syrupy" (3.11), and her condolences to Ella don't sound terribly sincere. Or sincere at all.
Still, she seems to think she has a chance with Ella's dad. She refers to him as "that charming man" (12.17) and is quick to say yes when he proposes to her. Around Sir Peter, Dame Olga is "kittenish, coy, and syrupy" (20.7). Thanks to the "blessing" of eternal love that Lucinda bestows at their wedding, she still loves Sir Peter despite being majorly ticked at him for deceiving her about his wealth (or lack thereof).
But she's not so loving toward his daughter.
Since Dame Olga's so in love with Sir Peter, she can't take her anger out on him for lying about still being rich. That, and he's constantly traveling. So she decides to take it out on Ella, despite Sir Peter asking Olga to treat Ella with respect. Olga pretends to agree, but sends Ella "a look of pure venom" (22.29).
And she starts right away, by having Ella's stuff transferred to the servants' wing, where she'll freeze in the winter. And then, once Hattie rats out Ella's obedience compulsion, Dame Olga orders Ella to do the most debasing, awful work around the manor.
Only Mandy's subtle blackmail (since Dame Olga loves Mandy's cooking) prevents Ella from being given to the laundress, who physically abuses her workers. Still, even Dame Olga's torture isn't bad enough for Ella to figure out how to liberate herself from the spell.