Dunning-Kruger, Impostor syndrome, and the sweet spot

To quote Wikipedia, the Dunning-Kruger effect is a cognitive bias in which people with low ability at a task overestimate their ability. This can be generally interpreted as “People who suck think they’re better than they actually are.” According to the social psychologists who coined the term, the very ability that these people lack is the one they need to objectively evaluate their performance. This is not true in all cultures, but is apparent in many.

Impostor syndrome, on the other hand, is a psychological pattern in which an individual doubts their skills, talents, or accomplishments. They have a persistent internalized fear of being exposed as “fraud”, hence the term “impostor”. Despite external evidence of their competence, these people think they do not deserve all they have achieved, and incorrectly attribute their success to luck, or interpret it as a result of deceiving others into thinking they are more than they perceive themselves to be.

It is important to steer clear from both of these patterns of thinking. To accurately and objectively evaluate your ability, you need a certain extent of competency, the willingness and trust in yourself to work towards that level, and the humbleness to keep working once you get there.
Someone told me that it’s good to stay right at the border between confidence and self-doubt. I think that is good advice.