We all know less and perform more poorly on certain things than we once believed we were highly capable with. As a cognitive bias, people will tend to believe they are competent before they truly are. In matters of self-awareness, it is better to profess as ignorant than to stand out with some bullsh*t effort you are completely unprepared for.
The combination of poor self-awareness and low cognitive ability will lead people to overestimate their capabilities. These often go hand in hand. No one can profess to be competent in all matters, yet some persist to do so. This doesn’t indicate that they are stupid, but rather they have not yet learned or practiced enough with a subject to have built a capacity with it. They are unaware, but not necessarily stupid.
Remain aware of your limitations on matters you know very little about. Before you would offer insight, make certain you are informed. The ignorant are often the most confident and the more informed are generally more subdued in the matter. Learn and apply for competence before you would share with confidence.
“Ignorance frequently begets confidence than does knowledge.”