Optimism can be a very powerful thing.  For a long time Americans believed that things would get better, and that caused them to take action to make things better, and that actually resulted in things moving in a positive direction.  But now things have abruptly shifted.  In late 2018, an increasing number of Americans believe that an economic downturn is coming, and they are taking actions consistent with that belief.  As a result, they are actually helping to produce the result that they fear.  And without a doubt, any rational person should be able to see that signs that the U.S. economy is slowing down are all around us.  So it isn't as if those that are preparing for the worst are being irrational.  It is just that when large numbers of people all start to move in the same direction, it has a very powerful effect.  We witnessed this in the stock market in recent years when people just kept buying stocks even though they were massively overvalued.  The collective belief that there was money to be made in the stock market became a self-fulfilling prophecy which pushed stock prices up to absurd heights.  But now that process is beginning to reverse as well, and ultimately the unwinding of that bubble will be quite painful.

Over the past couple of years the dominant economic narrative that the mainstream media was pushing was that the U.S. economy was "booming", and this encouraged businesses to expand and consumers to go out and spend money.