There is no way to foresee the unpredictable. Everywhere we turn there are potential calamities. And worrying about such things won't give us a shred of security. The psalmist found the answer to living joyfully in an uncertain world. Every hill and wave come under His careful attention.
Unpredictability seems like a reason for anxiety.
But the psalmist didn't have time to worry about what might happen. Instead, he made the choice to praise his Maker, who never loses control. We can make the same choice. Through all my earthly days, May nothing bitter quell, O Lord, My grateful song of praise. Even though you can't control your circumstances, you can control your attitude.