Why isn't life easy?

As a mother, the hardest thing for me is to watch my children hurt.  Whether it is a physical or emotional pain, neither are easy to witness.  I personally feel that watching my children in emotional pain is the worse.  My eight year old wears her feelings on her shoulders.  She has two settings, happy or sad.  She doesn't get mad, she doesn't get angry, and she never is out for revenge.  Unfortunately that sets her up for a lot of heartache.  She feels for others and allows them to run over her in the process.  My seventeen year old is tougher, but he gets mad.  Most of the time he focuses that anger on me.  He "blames" me for a lot of wrongs in his life.  I think he feels that I should be able to fix more than I can.  He knows that I'm not superwoman, but that doesn't stop him from wishing.