Anna was an obese child; during her formative years stylish clothing options were probably pretty limited.
A lot of fashionable people develop their sense of style through trial and error, especially during their teens and early twenties. It’s not effortless— you have to understand what looks bad on you to recognize what looks good and then translate that to whatever look you want to achieve.
The problem with Anna is that very little looks good on her, and during the crucial years when she would have been developing a sense of style there wouldn't have been much available. She may have felt so shut out from the very ideas of fashion or personal style, she just didn't bother.
Because Anna was a fat girl with limited options and no artistic talent, she never developed any taste when it comes to her appearance.
Don't forget--she was also the obese child of an obese mother, and back then adult women's plus-size fashion choices were a lot more limited as well. So her own mother was probably used to making do with whatever fit and was appropriate, rather than develop a style of her own, and thus had nothing to teach Anna when it came to how to dress.
There are certain colors that Anna has gravitated to that she looks good in, which makes me wonder if she "got her colors done" by some Mormon housewife doing those Color Me Beautiful consultations. Because, given how bad she can make herself look, and the fact she has no taste at all, I don't think she figured those out on her own.
She copies from other, more put together women but always seems to miss some crucial step, whether it be proportion, color, or fabric choice.
Yeh, and she hasn't got a clue how to accessorize. When you're as much of a fitting challenge as she is, and have so few good, ready-made options, the best defense is to have a massive wardrobe of accessories.
(In fact, were I to get into any sort of plus-size fashion startup, I wouldn't bother with any but the most basic clothes, and would focus on a line of accessories sized and scaled for fatties. It's a really underserved niche. )
She doesn’t seem to understand clothes and fashion at all which makes her little “fashion history” schoolmarming all the more confounding.
Her "fashion history" lectures are just pure cringe. They all come off as if she spent 10 minutes on Wikipedia, 10 minutes before turning on the camera or posting to Insta.
