Miserable people are not available to serve other people or to serve the Lord.  Their misery and self-focus has them sidetracked.  They do not know that if they serve others, then joy would not pass them by.  They have not learned that when you comfort another, then comfort comes back to you.  They have not learned that giving, loving and serving is the way into a brighter and fuller life.  Giving yourself rights yourself to others and to yourself.

“There were those who dwelt in darkness and in the shadow of death, Prisoners in misery and chains, Because they had rebelled against the words of God And spurned the counsel of the Most High.” Psalm 107:10-11 (NASB)