Fashion is completely subjective, as far as I see it. There are a lot of choices you have.
Unless you're sporting something like...intestines, I don't know, it can be "fashionable".
Certain styles work with certain people, and not everyone is going to fit every style.
Knowing which styles work best for you are part of being fashionable.
Now, I don't consider myself fashionable and I just sort of throw on whatever is handy.
Of course, that's generally jeans and T-Shirts.