The economy's overall performance can be compared to an individual, and their overall performance. It's well-known that the total "output" of an individual is positively correlated with the confidence they possess. What a person believes deep down about their ability and their chances of success will ultimately determine what they can and will become.
Belief = Performance!
The economy is driven by a similar set of circumstances. If the general belief is that the economy is doing well, and people (at least, collectively) have enough confidence in it, then, just like a self-fulfilling prophecy, the economy will end up doing well.
What do YOU believe about today's economy? Is it doing well or not, and why?