I studied math in college (twice actually - my second degree is in combinatorics, which means I can count reel gud). I spent a lot of time looking at, and solving, math problems.
One of the interesting properties of these problems is that you often can look at one and think “oh, I know how to solve that, I don’t need to actually do the work”. But, in fact, when you try to complete the problem, you realize you didn’t understand it as well as you thought (programming is often like this as well - you think you understand how to do something until you actually try to do it).
We’re all familiar with the idea of a bullshitter - someone who knows they are full of it, but pretends not to be. Once we understand someone is doing that, we’re usually pretty disdainful of them - it’s dishonest, and also not very useful. If you are looking for someone competent to do a well-defined job, having someone bs their way into the role is just irritating to everyone - they won’t be able to do the job, so it’s just a waste of time.
The tricky thing is that sometimes we become the bullshitters without realizing it - like in that math example. And sometimes this goes very deep , and we convince ourselves that we know what we’re doing, when we really don’t. There’s a very fine line here, of course, related to impostor syndrome: sometimes we convince ourselves we don’t know what we’re doing, when we really do.
Nobody ever thinks they are the fool in the Dunning-Krueger scenario. We all think we would be self-aware, but the definition of that syndrome is that you don’t have the tools to be aware, in some specific domain. So, you become the worst kind of bullshitter - one that fools yourself.
How do you stay out of this trap? I don’t know that anyone completely can, but the best thing to do is to be as honest as you can be about results. Like the working of a math problem, or the creation of a program, the results don’t lie about your actual ability. This is harder in some cases, like management, where the factors are complex, and failures might not be entirely your fault. In this case, try to look to track record and averages over time if you can.
We all fool ourselves from time to time, and in varying degrees. The best thing to do is to be on the lookout for it and constantly test yourself. The worst thing is to believe your own hype.