can't swallow these

why would people have the heart to do things that he/she does to another human being. 
why do people care less about how other people feel about them? 
why do people say things or express words that they don't mean?
if you know how hurtful it is to be treated like that, why do you do the same?
why do some people act so mean when all that he/she was treated with is full of love and care?
why does he/she ill treat others?
doesn't he/she has a heart?
doesn't he/she even bother that the actions hurts others so much that it is even so difficult for them to breathe?
and there is a pause
a pause in her/his life that she/he gets so confused
has she/he sin that much that God is trying to teach him/her to be more patience?