I am reminded of a phone interview I did at Google with someone from India. I started to ask him some very basic technical questions and he immediately got on his high horse - "These questions are far too elementary for me to solve. I'm a manager, I'm very senior."

The second time he did this, I said, "We have some world class figures working here, people you know, and they had to answer questions like this." I did not say that I was significantly senior to him too and had to answer the same questions.

He had no idea how to answer even very basic questions, it was painful. At the end I asked him, "Do you have any questions for me?" and he said, "No!" and slammed the phone down.

By contrast, a few weeks later I phone-screened a young man from Hungary. I had a list of questions and he just sprinted right through them.

I got to what I thought was my capper, and he said, with a charming Hungarian accent, "But this is a well-known problem!" I have heard this as an excuse before, so I said, "Not an issue, just tell me the answer," and he immediately gave me a clear and simple explanation.

I thought, "Hmm, maybe he's a ringer with a prepared list of questions," so I asked him a question I privately call, "What has it got in its pocketses?", where I simply ask about something I did the previous week.

He almost immediately came up with a solution - one much better than what I had done!

I thanked him and ended the interview. About ten minutes later, I got an email with an elegant and short program in C++ solving the "well-known problem".

He went on to a successful career at Google, richly deserved I might add.

If you don't know your fundamentals forward and backward, you will never be a world-class engineer, or even a world-class engineering manager.