Certainty and error.

I have found that I rarely make mistakes in subjects that I am uncertain about. This may be because I focus more intently on a problem if I'm uncertain about some aspects of the situation the problem exists in.

I am much more likely to make mistakes in areas where I am absolutely certain, but wrong.

I think this is probably common.

I think it is especially common is situations where people are judging other people.

On reason for this is no doubt found in the Jungian psychology of projection. In short, there are characteristic thoughts, impulses and emotions that everyone experiences but for reasons of upbringing or social mores we reject their presence in our own makeup because of the stigma that our society or upbringing has associated with them. This essentially makes us blind to the presence or effect of these thoughts, impulses and emotions in ourselves. However, for some reason, these thoughts, impulses and emotions refuse to be ignored. If we refuse to acknowledge them in ourselves, we will see them in others whether they are more strongly exhibited in others than they are in ourselves or not.

A useful example of this is found when we fall in love with a mate.

Our chosen mate tends to be perfect in every way but, once we are married to them, they change in ways that we find difficult to accept. More often than not, they haven't actually changed. Instead, the characteristics that we projected onto them that made them perfect are eventually disolved by our long-term experience with that person's true characteristics.

The point of this is that we frequently find certainty in life, and feel free to act on it, frequently to our own detriment.

Certainty should be viewed with more caution than uncertainty, because anytime you feel certain, your inclination will be to act as though you're right, even if you're wrong.