Understanding what self-confidence even means.
It is common in American culture for people to tell you to “just be confident” oftentimes emphasizing a “fake it till you make it” mentality. However, as with many pithy sayings that fall short if taken to the extreme, this also has its severe flaws.
“Let’s assume you have some ground-truth skill. That may be the ability to speak a language for example. Then self-confidence is merely acting in accordance to that skill set.”
First off, what does it even mean to “have confidence?” Let’s assume you have some "ground-truth" skill. That may be the ability to speak a language for example. Then self-confidence is merely acting in accordance to that skill set.
Some people are too uncertain and tend to undersell themselves relative to their skill set. Examples of this include imposter syndrome. Let’s take an example. If you are reading this, there is a very high chance that you have the ability to blink 3 times in a row (I apologize in advance for people whom this is not the case but you can choose any other trivial activity). Now, when you are by yourself, it goes without question that you can perform this activity. Let’s say though that we now have a million people watching you. Does that change your underlying ability to blink 3 times? Of course not! And in fact, whether you are alone or have a large audience, it makes sense that you should be acting according to your belief that you in fact can do this!
One counterpoint is to say that having a million person audience watching you increases the “risk factor” in the sense that these people can be judging you if you “mess up” which can have damage your reputation. While that may be true to an extent when “all eyes are on you,” acting in confidence means that you can effectively operate according to your true skill sets, regardless of the audience.
Some people are in the opposite camp. They act above and beyond their true skill set which we call being overly confident or in its extreme forms, being cocky or delusional. They may be able to get away with it for a while but if they cannot “grow into” the level of skill they project, then people will consider them a fraud in the long-run and they will ultimately lose credibility.
So what is the best level of confidence to have? In general, I would recommend always projecting slightly more than your underlying skill set (i.e. slight overconfidence) not as a way to deceive, but rather as a way to keep pushing yourself forward and growing. Challenging yourself appropriately is the only way you can improve your underlying ability.