Aggravation

Do you know the serenity prayer? "God, grant me the serenity to accept the things I cannot change, courage to change the things I can, and wisdom to know the difference." I am really struggling with this right now. How do you motivate someone who refuses to be motivated? How do you let them fail and fall, when you can see where they are making mistakes and you know their life would be easier if they'd only listen to you! How do you serenely accept the things you can't change? What if you gather the courage to change the things you can and it blows up in your face? How do you accept that some things are out of your control, no matter how much you want to help? It's one thing if it's just affecting the one person, but what if there are children? Or others who are being adversely affected? When do you stop beating your head against that brick wall?