White pants and black thongs. Really white pants and any sort of colored/bright/contrasting underwear of any style.
Soft shell jackets that are too small. I really like the soft shell jacket trend and would love one of my own, but there was a girl I kept seeing at shows this year who was very skinny and had a SUPER tight soft shell jacket. It seriously looked like she was vacuum packed into it! The effect was not unlike a praying mantis on horseback.
Oh I also don't like the show shirts on girls where the top button starts really low! The ones where the top button is below boob level. They just look horrible! Also the majority of people wearing the short coats do not look good in them. Longer coats are much more flattering to most people especially if you have a long torso.
show bow show bow show bow. There are a million ways to wear hair out of a helmet and have it look show appropriate. THAT IS NOT ONE OF THEM.
Personally, I dislike really flashy belts in the hunters. If you won't wear a hot pink saddle pad, don't wear a hot pink belt! It distracts away from the so close to clean appearance.
Also not a huge fan of the big hair bows for the same reason. Very simple ones of one colour that don't cover the number and flap around are cute. Ginormous beasts that fly around like a flag need to go.
I just started showing breed shows vs H/J shows this year - and although I know it's "traditional" and even in the rule book for when I was looking at the Pinto shows - I loathe the fleece number pads.
I much prefer the streamlined look of numbers on backs and a fleece half pad under the saddle.
Also - rust breeches. I don't think I will EVER like that trend.