Worry?

The seventeenth century philosopher, Baruch Spinoza thought of worry is “an inconstant pain” arising from the thought that something bad might happen in the future.  For Spinoza, worry is essentially future oriented.  Even if our focus of worry is about something that happened in the past, it is only in relation to how it will affect our future.  - Rabbi Gregory S. Marx

So what does this mean?  That we spend invaluable, irreplaceable time agonizing over what only  might come to pass?