I've been re-reading an interesting and well-known book by Philip Yancey, Where is God When It Hurts? Among his many contributions, he raises an interesting prospect regarding what the world and life would be like if it were entirely fair. Suppose every act of good would immediately be rewarded with warm fuzzy feelings and every act of evil would cause intense pain. Life would be fair, because the consquences of our choices would be immediate and unmistakeable.
However, in terms of our soul it would be like living in a B.F. Skinner Box. We would become conditioned to behave the right way. And the side effects would be monumental. As all of our actions grew directly out of our own immediate interest, there would be no courage to do good, no needs around us to be met (everyone else's life is already fair before we get there), no insurmountable struggles to overcome. No trust would be necessary because every well-intentioned act would turn out well. If we follow this pattern far enough, we will see that relationships themselves take on an entirely different form that what we have today. And it is not for the best.
God did not want human beings to respond to Him and for Good simply because we were conditioned to do so. He is not a behaviorist. God is relational. And He wants our love freely given. He wants us to migrate toward Good because we desire what is good; not because we have been conditioned to do so.
Yes, there are general principles at work in our world, such that good leads to life and evil leads to death. But the relationships are not so fixed and obvious that we are reduced to reflex responses. We actually do make choices (although our will is heavily influenced by our sub-conscious processes) and take risks. That changes everything.
A world were life was always fair would be a lot less painful. But it would also be a lot less alive. The world we have is not fair and life is a lot harder as a result. But our world is also filled with goodness that is truly Good and Redemption and Hope and meaningful purpose. As hard as it might be, I think I'll choose this one.