We are not to be blind to the very real threats of evil in our lives. Seeing them for what they are only gives us greater cause to praise and thank God for working in them with perfect control and authority. But we are not to be pre-occupied with the appearance of evil around us. See it, admit our helplessness to cope with it in our own strength, then turn to God.
To praise God is to express our acceptance of something that God is permitting to happen. So to praise God for difficult situations, as sickness or disaster, means literally that we accept its happening, as part of God’s plan to reveal His perfect love for us.