I think a lot of this is because our profession does not have an accepted universal bar everyone can jump over to be considered ‘qualified’. Every technical interview feels like rolling the dice in proving I am a competent developer. Giving me 50 minutes in a high pressure situation in an environment i am unfamiliar with and people I just meet will never product my best results, and then add to the fact that I could…
My focus is security, and so the second time around I got Travis Ormandy as an interviewer. I was able to impress him well enough with my IPSec foo to make it onsite. Then I got asked a question I had already been asked in another interview with another company, and I was able to knock that out of the ballpark (I mentioned I already knew that question, but the interviewer wanted me to answer it anyway). Then I got asked a question that used recursion, and because I took a graduate course on induction and recursion within the past year, that was effortless for me. Then I got asked a question that involved a kernel feature, and because I happened to recall the Linux kernel list macros and semantics (something I couldn’t repeat now over 10 years later), I really impressed that interviewer.
I ended up having a really successful part of my career at Google, even though I ended up not really writing much code when all was said and done. However what code I did write was highly impactful.
Looking back, things could have gone very differently if I had gotten a different set of interviewers and/or questions. The questions I got just happened to coincide with what was “paged in” to my “working memory,” so to speak.