I don't understand fashion

I just don't. I've been trying to pay attention to magazines and trends, getting ideas for fall. Truth be told I think 90% of the fashions look ridiculous. I live in a ultra-casual city, you'd be laughed out of the grocery store in the outfits they show for "weekend". Yet it depresses me to the street full of people in t-shirts. I'm trying, but I'm not sure I'm getting this...