To be human in a fallen world, is to be anxious. Scripture sees anxiety as being both fearful of what might happen in a world where bad things do happen, and death is certain. But anxiety is also seen as a motivation to live out God's will in Jesus during this life, with a sense of personal responsibility in light of God's will, and for others.
Soren Kirkegaard is one who profoundly thought through the concept of anxiety. To Kirkegaard there was objective and subjective anxiety, as well as good and bad anxiety. Indeed to live as a human was to accept anxiety or else live in despair. Anxiety was meant to help one become what God intended for them in Christ. And a reality that never ends in this life. Though anxiety could have the opposite effect so that one can end up in despair, giving up and thus abandoning faith in God's promises in Christ, and therefore missing God's good will for them. Kirkegaard has a number of interesting things to say about anxiety in light of the fall and God's redemption in Christ, largely missed since philosophers referring to his insights into the human condition, have set aside Kirkegaard's theology. For Kirkegaard the proper end of anxiety is to rely on God's provision of salvation in Jesus Christ, and to (even joyfully) rely on Christ fully in one's ongoing existence.
Anxiety has been an ongoing issue in my life. I've grown in overcoming it much over the years, and handle it better when it comes now. I can see the wisdom of making the right kind of anxiety a part of my life, to help others by prayers and loving acts and words (1 Corinthians 7 has some examples, as well as Paul expressing his godly anxiety over the churches, and Timothy sharing in that). Most importantly I can see a good anxiety in endeavoring to live each day as one following Christ in the community of God's people and in mission to the world. Motivated to do God's will. Jesus himself seemed to express such in light of the cross, and in this sense anxiety can help us to order our lives before God.
As to the bad anxiety, we must be assured that in Jesus, nothing at all can separate us from God's love. Whatever we go through, God will be present for us, and the end will be good. This must become dominant over those matters which can deter us, and I know of them well. So that we learn to cast our anxieties on the Lord, knowing of his care for us.
Just a few thoughts on this; the chapter has many more. And what more would you like to add?
(From reading from The Consolations of Theology, edited by Brian S. Rosner, the chapter, entitled "Kirkegaard on Anxiety," by Peter G. Bolt.)