Our value is only because of God.
15 Precious in the sight of the LORD is the death of his saints.

16 O LORD, truly I am your servant; I am your servant, the son of your maidservant; you have freed me from my chains. 

The Psalmist concludes that its better to be alive to continue being the king than to be dead. But how can the Lord be precious if He has taken those we love away from us?Because he expresses His being freed from the chains of death in verse 16 i do not believe the Psalmist is happy that God took his friends. Rather I believe that the Psalmist is saying that sustaining life is more important than what the Psalmist does. And you will find this reasoning throughout the Psalms. He is saying the only reason that I am able to return to God for His goodness is because He freed me. But its because God considers life more important than what a man does. I really do not think anyone can understand Gods side of bringing His loved ones to himself.  But they went to God and that is why they are valuable. He reduces Gods work to simplicity.

 The Psalm is really about God answering the Psalmist prayer to be saved from death. So i believe its saying that we should be thankful that we are alive. Thats all God requires. And so what is mans part? Its to see that a persons life is valuable because it belongs to God. And therefore we should under-gird each other.. all of our help to those who are suffering should be pronouncing blessing upon them and cursing for their protection and to see that they are valuable just being alive. As the Psalmist prayer was answered in the simplicity of God speaking His word so each life is valuable because they belong to God. In this way sometimes just "resting in the Lord" is not doing much.