Even knowing that she's evil and manipulative, Lady Susan's view on "accomplishments" deserves a mention.
I was so much indulged in my infant years that I was never obliged to attend to anything, and consequently am without the accomplishments which are now necessary to finish a pretty woman. Not that I am an advocate for the prevailing fashion of acquiring a perfect knowledge of all languages, arts, and sciences. It is throwing time away to be mistress of French, Italian, and German: music, singing, and drawing, &c., will gain a woman some applause, but will not add one lover to her list — grace and manner, after all, are of the greatest importance.
Catherine Vernon is the only one willing to stand up to Lady Susan and she's not blinded by her charms. She's the only one who actively protects an abused teenage girl from her manipulative and villainous scheming mother. That is awesomeness, Mrs Vernon!