Answer:
I belong to you but others use me more often than you do
I can fly but I have no wings. I can cry but I have no eyes. Wherever I go darkness follows me.
Lighter than what I am made of, more of me is hidden than is seen. What am I?
I am a box who holds keys but not locks. With the right combination I may unlock your soul
Part carbon, part water, I am poison to the fishes. Many falsely claim my name, I am the pause that refreshes. What am I?
Whoever made me don't want me. Whoever bought me don't need me. Whoever use me don't know me.