http://theanxietytips.com/what-are-the-benefits-of-anxiety/

Anxious people are known for having a mind that runs constantly. They are always thinking of the what-ifs in life. Anxiety is a driving factor in those people who are always running different scenarios in their minds. “What would I do if I got a flat tire on the way to the airport?” or, “What happens if lightning strikes the tree outside my house?” The anxious person is usually best at calculating risks and coming up with solutions before a problem even occurs. In a dangerous situation, the anxious person has probably already pondered the situation beforehand and will most likely be a driving force in implementing the solution. (http://theanxietytips.com/what-are-the-benefits-of-anxiety/)