PLAYING GOD - Saving Other People

"THERE IS A FINE LINE BETWEEN GIVING FREELY TO OTHERS AND PLAYING GOD."



In the book I'M RICH BEYOND MY WILDEST DREAMS the authors warn against trying to replace God by saving people in trouble.
We have also been taught that charity is a God-quality.

What is the difference between charity and playing God?

How can we know when we have crossed this fine line?