I've gone into every job interview I've had with the attitude that I'm a hot shot who is gracing my employer with my willingness to work for them[1]. I've gotten offers at about 50% of them, which means that I've turned down more companies than have turned down me.
Confidence really does work. If you sincerely believe in your abilities, it's much easier to convince others to believe in them.
[1] This is not mutually exclusive with respect or humility. It's quite possible to believe you have a lot to offer your employer while also believing they have a lot to offer you, and then the job interview process is just a matter of negotiating the right fit.
Interesting. Whenever I see aggressive confidence in an interviewee, I immediately think Dunning-Kruger because statistically it's by far the most likely cause. Either way it's down to empirical evidence though.
Anyway, as far as anecdotal evidence goes, I tend to intentionally give off a pretty neutral vibe and rarely worry about flunking an interview. (I chalk it up to mad skillz rather than body language though.)
One could also argue that your willingness to quickly diagnose an individual coping with a traditionally high-anxiety situation (interviewing) with trendy cognitive bias issues calls your ability to recognize your own weaknesses into question.
Confidence really does work. If you sincerely believe in your abilities, it's much easier to convince others to believe in them.
[1] This is not mutually exclusive with respect or humility. It's quite possible to believe you have a lot to offer your employer while also believing they have a lot to offer you, and then the job interview process is just a matter of negotiating the right fit.