It could become exclusively negative and as a consequence, very very dangerous. It could become the cause of a complete collapse of our spiritual life. If I feel that there is no other reason for suffering than punishment for sin, this could develop in us a distorted image of God where God would be to us like a policeman with a big stick lying outside our door in the shadows waiting for us to make one mistake so that He could clobber us. It could give us the idea of God's being sort of a drill sergeant or a Father who abuses His children. And that would be fatal for our spiritual life.
Nobody knows the reason of suffering.
It's one of those great impenetrable mysteries of God's holy wisdom. All we can do is accept it from the hand of God, accept it from the hand of our heavenly Father. Believe that God loves you no matter what He does - even if He kicks into you. Accept it in the strong hope that it will be for your benefit in the long run, even if it hurts at the present moment. We don't know why God gives us good things.