People always say that worrying is unproductive. It does not add to the solution and in fact, hampers the thought process of a person in arriving at a solution. But one thing is certain, worrying is an immediate response to any given problem. Even the most optimistic person cannot deny the existence of this emotional reflex.
I think worrying is what makes a person evaluate the situation. In a fast life, worrying gives a person that much needed break from a life on auto-pilot mode. Worrying forces a person to put things in perspective. It contextualizes the problem and prepares the person for the eventual acceptance of the situation. The most effective reality check as I call it.
I believe that worrying can also be a motivation to move forward. Because worrying is usually coupled with panic and self-doubt, people tend to get uncomfortable at this stage. Thus, nobody really wants to linger in worrying, unless of course a person is a masochist or a chronic worrywart. Worrying compels a person to decide whether to progress or regress. A fork in the road that one has to take.
Lastly, and on a more personal note, worrying celebrates our humanity. We are not invincible or perfect or a robot who acts under a given set of instructions. There are things that are valuable and meaningful to us, which cause us to worry more about them than with other things. To worry is to acknowledge that our lives truly matter.