it's like the eye of a duck

I'm the opposite -- I always stop and compliment. Even a short line like "Kewl boots" would have done the job. If you add a "Kewl boots/hair/jacket -- wish I had the guts to wear that/those" it only adds to your own kewl factor, and raises the goth's self-confidence. Goths, as you well know, face so much misunderstanding and hate, that I think it's a good thing to stop and basically say "Yeah, I look like the typical 'burb matron now, but it's all a cover because under these wrinkles and jobclothes, I totally identify. You rock."