A "lifestyle" in which people want to be different from everyone else and show that they don't care what everyone else thinks.
They typically don black eyeshadow, dye their hair black, wear black clothing that makes you think "bondage" and act like they hate the entire world. Typically, not everyone. This way, they can act EXACTLY LIKE everyone else who claims they "want to be different and don't care what everyone else thinks.
Oh come on, we all know someone like that. Poor bastards just need a hug, is what they need.