The Dunning-Kruger effect is a cognitive bias, which refers to the tendency for people with low ability in a specific area to overestimate their abilities in that area. It featured in the work context recently, as I used to have a co-worker who thought that they were very brilliant, when in fact, the opposite was true.
It was a frustrating experience, for me at least, who needed to deal with this co-worker several times. Things needed to be completed, but didn't happen. There were deliverables that were agreed upon, but of course, those didn't get delivered. And as much as one wanted to steer things and course-correct, this was all to no avail.
The frustrating thing is that this individual somehow didn't even comprehend that things were not going well. They thought that they were very brilliant in what they are doing, and therefore couldn't understand why the rest of the world and their grandmother were frustrated at them. I never recalled this individual admitting mistakes, instead they thought that their methods were always superb and worked. Until one day, it didn't, and while the rest of the world moved on and learned new skills, this individual was still trapped within their old ways, and unfortunately, these old ways weren't working anymore.
It took a while, but eventually, things have changed, and I don't have to deal with this individual anymore. I have to admit, I breathed a sigh of relief.