A young Scottish student was studying in the United States.  He became functionally blind to the point that other people had to read to him.  He was in love with a young woman, but she broke off their engagement when she heard of his blindness.  Twenty years later he came to a day when he felt totally alone.  His family had gone to the wedding of one of his sisters. His old fears came back and he was angry about what had happened to him.  The pain of love that was not returned kept coming back to him.  He was hurting to the point of despair, but then George Mathison came to himself, or rather God came to George Mathison, and he wrote

"O joy that seekest me through pain.  
I cannot close my heart to thee.  
I trace the rainbow through the rain 
and feel the promise is not vain - 
that morn shall tearless be."

It's not easy, but some people can do it.  They can see the rainbow in every rain cloud.  Those I know who can are persons who have a strong faith in God.