What makes life,hard and difficult?

I'm not prone to looking at things from the negative viewpoint, however it is an interesting question.   Sometimes circustances and the luck of the draw, make life hard and difficult.  Consider those who are born or who contract disabilities, did they do anything to cause their predictament?  Or the child born into poverty and ingnorance?  I don't have answers to those type of questions, however, I do believe we sometimes make our lives hard and difficult by our own actions or lack of actions