Any benefits to expecting the worst?

When I was waiting for my annual grades to come out in school, my father loved to say ‘expect the best but prepare for the worst’ by way of advice . I never quite took his advice to heart and now it looks like that was just as well. This article in Nature magazine suggests there are few if any benefits to expecting the worst and the only folks who benefit from dong so are those that motivate themselves to do better from a fear of failure.