Thomas Edison once said, "Show me a thoroughly satisfied man, and I will show you a failure." He is absolutely right.
That is not to say that we should not be spiritually content. Spiritual contentment brings glory to God. John Piper said, "God is most glorified in us when we are most satisfied in Him." Contentment should be found in our relationship with God. However, each of us should be totally discontent with our current level of accomplishments. For when we become satisfied with our achievements, we tend to hang where we are and cease to move forward. And when we cease to move forward we miss seeing and experiencing all the amazing things that God determines to do through us and for us. Successful people continually live with a motivating sense of discontentment.