Anger, frustration, hurt. A desire for someone else to feel the same; but it is internal, insipid and eventually hurtful to yourself. Yet we, (humans that is) continue on, hoping that someone else will feel this pain. That they can look into a mirror and have the pain that they cast out, reflected back at them.
In reality, it is this hope, this desire, that is cast back on the hopeful. This bitterness that burns with acidic force, and damages those who can least afford it.