First, I hate fashion, so my list of my hated clothing is short and usually the hate is aimed at the practicality of the chosen article of clothing.
I agree about Uggs, they're gross looking, and look like they would ABSORB water, which is not a good feature for a boot.
Crocs: filled with holes and made from cheap (but still costs you 60 bucks) rubber.
Those slipper things all girls at my high-school insist on wearing, apparently, they cost upwards of 30 bucks, which is half of what my good sneakers cost, and the sneakers have about 10 times more material on them then those pathetic excuse for shoes.
Ultra-baggy/long clothes... you look ridiculous, pull your pants up past your knee's, please.
Boxers, why do people thing it's cool to wear shorts under your pants? Maybe because people wear their pants at the knee's, possibly because the latest style is jeans that have been through a threshing machine? Which brings me to my final one:
Faded/torn jeans... you pay extra for this? REALLY?!?