Age of Anxiety.

Anxiety is the dizziness of freedom.

Just as a physician might say that there is very likely not one single living human being who is completely healthy, so anyone who really knows mankind might say there is not one single living human being who does not…secretly harbor an unrest, an inner strife, a disharmony, an anxiety about an unknown something or something he does not even dare to try to know, an anxiety about some possibility in existence or an anxiety about himself…an anxiety he cannot explain.

Soren Kierkegaard, The Sickness Unto Death

If man were a beast or an angel, he would not be able to be in anxiety. Since he is both beast and angel, he can be in anxiety, and the greater the anxiety, the greater the man.

Soren Kierkegaard, The Concept of Anxiety.