According to Matthew, Jesus believe that the second most important thing in the world for his disciples to grasp, should they want his life, was the absolute necessity of feeling.
He said it this way, "Blessed are those who mourn."
Mourning is only possible for those who feel. I have a buddy who speaks of a time when he was so immersed in the ways of the world, so consumed by his own self-interests that he was emotionally numb. He speaks of the days when he would lay down in iced baths just to feel. Just to remind himself that he was alive. Ephesians 4:19 speaks about this emotionless condition.
But not all feelings are listed in the Beatitudes as blessed. Worry isn't. Jesus actually says that we should not worry (Matthew 6:25). Anger isn't. Paul warns us not to even let anger stick around for one day (Ephesians 4:26). Guilt (or shame) isn't. Peter says that life in Christ is shameless (1 Peter 2:6).
No it is sorrow that is blessed. Sadness. Sadness about our own sin, sadness about the sinfulness of others, and sadness about all that is wrong in the world.
Yes, there is something productive and right about sadness. About caring deeply about things that God cares about. It is the only emotion that does not lead to a dead end.
Because, Jesus says, it will be comforted.