Why are healthy individual finances important to the Economy in North America?

The answer to this question is if you were to get laid off your job you would cut back your spending which influences the economy and local businesses.

By doing this, you will always have some sort of safety net in case anything bad happened to your main source of income (such as getting cheated by your co-workers, bad economic conditions on nation-scale, your corporation is beaten up by the competitors, etc)