It varies a lot from person to person. A lot of people dress to follow trends or rebel against them. I find those attitudes very purile, they don't show a lot of taste and are too closely connected to the choices of others.
My choices in clothing, design and music have always been in part related to my ideals, and then in part related to how I perceive my identity (which it would be a derail to discuss). Then of course there's a part of me that just doesn't give a fuck. After all, I am a guy, haha.
Well artistic communication is always open to interpretation. It's not exactly direct.