Praying about everything is not enough. We should also express our gratitude to God for everything he has done for us. Then, we will experience inexpressible peace.
Again, I don't know if this means we should be happy with everything. However, it should affect how we perceive everything.
Many of the Psalm encourage a review and a remembering of God's Works. People are prone to forget. People are prone to focus at the close to hand. If what is at hand is bad, people are prone to focus on the bad.
Focus on God's grace and provision brings a greater awareness and understanding of God's character, commitment to people, and is an encouragement to faith and trust.
Peace is created as we come to greater realization of who is concerned for us, and who is active on our behalf.