Don't get me wrong; I think there's some amazing, beautiful, and ingenious steampunk costuming around.
And then there are the ones where the designer thinks that all they need to do to be steampunk is to throw on a liberal sprinkling of cogs and gears as decoration. Some of it even looks pretty, but it's still stupid. The whole point of steampunk costuming is to create an illusion of functionality, so random bits of brass stuck together work, being obviously non-functional, work against the illusion.