When you fail to reach a goal - say, for instance, you give an important presentation and it doesn't go well - you become the detective (once again, largely unconsciously). You gather up the usual suspects to see who is responsible for your failure: lack of innate ability, lack of effort, poor preparation, using the wrong strategy, bad luck, etc. Of all of these possible culprits, it's lack of innate ability we most frequently hold responsible, like the much-maligned butler in an Agatha Christie novel. In Western countries - and nowhere more so than in the U.S. - innate ability is the go-to explanation for all of our successes and our failures.
The problem is that the evidence - the kind gathered by scientists over the last thirty years of study of motivation and achievement - suggests that innate ability is rarely to blame for either succeeding or falling short. (If you've blamed your poor performances in the past on a lack of ability, don't feel bad. We've all done it. The butler seems guilty. Just please don't do it anymore.)
If we are going to ever improve performance, we need to place blame where it belongs. We need solid evidence about where we went wrong. Unfortunately, that's the kind of evidence that usually doesn't make it to our consciousness on its own, making self-diagnosis practically impossible. We need help getting the right answers.