Why was the period following World War I called "the age of anxiety?"

Many people saw World War I as proof that many of the things Western society was based on were essentially a lie. Progress, a rational worldview, patriotism, and religion all seemed irrelevant to people who had witnessed the carnage in the trenches. The period also witnessed a great deal of social unrest in Europe, where wildly fluctuating currencies, radical political leaders, massive strikes, and other social unrest contributed to a feeling of unease. Then there was the rise of the Soviet Union in what had been Russia. This development, especially when coupled with the economic downturn of the late decade, caused many to question western style capitalism. So in short, the period was one of major political, economic, social, and even intellectual uncertainty. The most poignant part, looking back, of course, is that we can see that the anxieties were, in the end, quite well-founded, and that dictators were able to exploit them to rise to power.