Another reason is to broaden us in our sympathy and understanding of each other. The one who has had but little trouble in life is not a particularly helpful person. But one who has gone through many trials, shattered hopes, and tragedies, has learned a valuable lesson. Those who have learned through experience are of great value.
“Blessed be God, even the Father of our Lord Jesus Christ, the Father of mercies, and the God of all comfort; Who comforts us in all our tribulation, that we may be able to comfort them which are in any trouble, by the comfort wherewith we ourselves are comforted of God.” II Corinthians 1:3-4
Then you can enter into perfect fellowship with a person who is in unspoken agony of spirit and pressure of trial, and pray with compassion and understanding. Then you are able to look beyond the frailty of flesh, and remembering that we are all but dust, are able to trust the Lord with a sublime faith for change and victory in the lives of those that The Lord would have you minister too.