Is it perhaps the story behind that faded dress or is it the possibility that you could start your own story while wearing it?
Vintage is cool because you're pretty much guaranteed that no body else is going to have the same thing. When you walk into a true vintage store, there's racks and racks of clothes, all one of a kind.
The best part is when you find the one perfect skirt and you check the price tag, just waiting for that jolt of disappointment when you realize, oh, this isn't my size; and it never comes. It's your size and you buy it.
Or maybe the best part is when someone says, "I like your shirt," and you get to reply offhandedly,
"Oh thanks it's vintage."