The effect of suffering is to make some people better and others worse, according to their attitude and reaction to it.  We see this at the time of the Crucifixion.  The bad thief was made worse by suffering and died cursing Christ; the good thief was made better and he accepted his death as a just punishment and turned to Christ in penitence and faith and hope.

Suffering can also do good by rousing compassion in others.  That is most obvious when there is a dramatic accident or disaster, whether it be a pot-holer trapped deep underground, or a community struck by an earthquake.  People work without thought of self in order to rescue and help the victims, and they become better people as a result.

So at the Crucifixion, when Jesus said, “I thirst” (RSV, John 19:28), one of the soldiers on duty gave him some of the wine he had brought for himself.  That act of compassion made that soldier a better man.