Dissonance

The majority of people have been shown to judge themselves above average in intelligence, driving ability, and other attributes. This illusion of superiority causes us to have difficulty in admitting failure and leads us to blaming others and/or rationalizing about circumstances. "Surely there were extenuating reasons why I failed, it couldn't have been my fault, after all, I'm smart." Failures and mistakes do not correspond with our self-image.

(Conversely, if you are among the minority who think themselves below average, you reinforce that negative mental image by explaining away successes, "It was just a fluke." "Before you know it people will find out how truly stupid I really am.") 

Now that I am aware of this inherent tendency, I try to alter my perception of myself and try not to give in to thinking of myself as smart, but rather try to think of myself as one who desires to learn and persevere. This has its own set of accompanying biases, but I prefer those to the ones I'd held for too many years.

To admit that I had wasted years - yea, even decades - in a fruitless, nonsensical delusion, and worse yet, subjected the people I love the most (my children) to the same delusion, was a deeply wrenching experience, to put it mildly. As I wrote in my introduction, this is what prompted my search to understand how such a dreadful and far-reaching mistake could have been made in my life.

I wasn't the "good person" I thought I was, and I certainly wasn't very smart.