How many long for a day when they felt more needed and useful? Others long for such a day in the future. We measure our significance by how much people need us. It is not that we are not to do the things that Job longed to do again. It is that our ability to do them in a way that we measure as significant does not define who we are.

" because I delivered the poor who cried for help,
and the fatherless who had none to help him.
The blessing of him who was about to perish came upon me,
and I caused the widow's heart to sing for joy." - 
(Job 29:12-13 ESV)