How To Worry Productively

Why do we worry? Is it to try and plan and anticipate a situation?
You can either plan,  or you have enough experience not to, both make you equipped for the pending situation.  This is why we worry,  it's our way of 'planning' for up and coming events. But what if you're already prepared, what if you already know what to do but you don't know it? What if you can't actually plan for the event your anticipate and you're already prepared as much as you can be. What if the best strategy is to deal with something in the moment because you have enough experience to handle it better than any 'preparation' could do?