There is a sadness which is biblical. Jesus wept and cried.
Often the church wishes to distance itself from sorrow. The Christian must always be happy.
Paul described himself as sorrowful but always rejoicing. You see the world is difficult and as Christians we are called to live in and participate in the world.
Often the sense that Christians must always be happy is simply to say that Christians must live in a state of delusion. We are not meant to be happy at all things.
We are meant to have joy which is a deep seated satisfaction in God even in sorrow. Sometimes even this fails, but you see it is not the end.
It is true faith to say, "Lord I believe help my unbelief." We know we love God when we walk through hardship.
You see anyone can say they love God if they have never faced pain and suffering but when we continue to love God when it does not from the worlds perspective make sense our faith is most clearly seen as real.
This is why the bible always says that when we are weak we are strong. You see in our weakness we live by faith. Our strength is Jesus fully man and fully God forever. When we rest in him we are strong.