Dressed in Black, is the most lovely song I have never heard in my entire life. This song tells the story of a person whose true-self had to hide from rest of the world because of this person untrusted people, this person closed its heart to those who surrounded it. In my opinion, this is NOT just in relationships.
"I had given up"
"I didn't know who to trust"
"So I designed a shell"
"Kept me from Heaven and Hell"
This occurred for an unknown thing because we cannot find proofs in this song, but the rest of the album 1000 forms of fear tells us.
Sia, this person probably, was really affected by this. Maybe she was insecure, afraid, or in pain (as the song Cellophane apprises).
Quotes like "I had hit a low", "I was in prison by dark", and "I was scared, I was torn", and more show a negative impact in Sia.
Sia was wary of this and she pushed herself to close herself for her own good (I KNOW thanks to other tracks of the album 1000 Forms of Fear that this is true, but you still can predict that Sia pushes herself to close her heart, to stay in her "shell").
" Was all I let myself know"
"I'd given into the fight"
"And I slipped further down"
But then, there was somebody strong headed enough who took the apprehensions to care about Sia. This person gave Sia what she had lost, love, comprehension, understanding, everything she had lost. This person took the nest out of Sia and she put her love back in this outstanding track.
"You found me dressed in black...
Covered my heart in kisses"