Why do people who come from broken homes do this?

I am from a broken home but I am grown up now. People like that are hurt inside, they don't understand what it is like to be "whole" and "happy". Even if they know the split up was not their fault it still leaves scares and doubt. Some try to fix this brokenness with alcohol or drugs. They will even try to make you feel bad so you can understand how they feel inside "Misery Loves Company". There isn't really anything you can do to fix them other than kill them with kindness and show them you have confidence in yourself.