Ugg boots with skirts or over jeans.
Please make this trend stop. I understand they're comfortable...I own a pair of Uggs. The fact of the matter is they belong under jeans or sweats, not over pants or with a skirt. When worn with a skirt, they make your legs look stumpy and chubby. Not to mention, you should always dress for the climate you're in...and wearing Eskimo boots with a denim mini makes you look foolish. Wearing them over jeans makes you look ridiculous. It makes no logical sense and is uncomfortable.

Belts over shirts.
Someone's going to the gym after work! Honestly, who thought the idea of wearing a weight belt over your shirt was a good idea? Unless you're a weightlifter or UFC or WWE champion, I don't want to see a belt anywhere but threaded through the loops on your pants or skirt.

Ballet flats with anything but pants.
Like Uggs, I know they're comfortable. These look really cute with a pair of jeans or casual pants. Please don't make the mistake of wearing them with skirts or shorts. When you wear ballet flats with skirts, you look like a 5 year old. Also, the reason why women wear heels is to make their legs look better. Conversely, ballet flats don't flatter your legs one bit.

Bermuda shorts.
I have absolutely no problem with shorts. I have absolutely no problem with capris. I do have a problem with the middle ground. I've seen precisely zero women look good in bermuda shorts whether they are plaid, solid, denim or any other fabric. They serve no purpose, are unflattering, and if you want to wear shorts that bad then wear normal shorts!

Tight jeans with big sneakers.
No thank you Ashley Simpson. No thank you Avril Lavigne. You look horrible when you wear big, clunky Nikes with skinny jeans.