The impostor syndrome, sometimes called impostor phenomenon or fraud syndrome, is a psychological phenomenon in which people are unable to internalize their accomplishments. Despite external evidence of their competence, those with the syndrome remain convinced that they are frauds and do not deserve the success they have achieved. Proof of success is dismissed as luck, timing, or as a result of deceiving others into thinking they are more intelligent and competent than they believe themselves to be.
via Impostor syndrome – Wikipedia, the free encyclopedia.
I have a good number of friends who have this. Especially my more atheist leaning friends. I suppose it makes sense: the more you believe that we are the product of our environments and genetics the less you can take credit for your actions.
Anyway, it’s destructive, so stop it.