They make a few quick pecks and then look around to see if they are in danger. Their constant anxiety causes them to interrupt their eating every few seconds. Evidently, Jesus' teachings about anxiety have some limitation in their application. Paul had anxieties. Other evidences of his anxieties are seen in the Scriptures.
Some anxieties are helpful.
They stir us to appropriate activity to relieve the need or solve the problem. They move us to treat our cancer, search for the missing child, work to evangelize the lost, and to pray and to depend upon God. He was spurred to do greater things then. Fear, rightly directed, is the father of courage. It stimulates the adrenaline and brings out the best in us.