The question he arrived at is: “... will you please tell me about the best project that you’ve ever created?”
Then watch for enthusiasm and pay attention to the details. The goal seems to be to identify someone who really enjoyed and takes pride in a program they've written.
The "project you're the most proud of" might be a more precise way to phrase it because "best project" could mean either:
- created the most value for your employer even if it was a soul-sucking nightmare / merely maintenance project with no challenges.
- you learnt the most from it / overcame challenges you didn't know you could / came up with moonshot solutions to issues no one even realized were there.
People can be proud of either of those accomplishments as well.
Honestly, I doubt "most proud" versus "best" makes a difference at all. Candidates generally explain their answers to these open ended questions. If they (for some reason) don't recognize the implicit, "And why?" part of the question, you just follow up with it.
The conversation will never be just, "Foobaz, next question." One way or the other, it will be, "Foobaz because..." It saved the company $2M/year. Or users really loved it. Or it improved the engineering process and made releases faster and lower risk. Or it was a really tough problem that required a lot of creative thinking. Or it taught me a lot about 3D game programming.
The question he arrived at is: “... will you please tell me about the best project that you’ve ever created?”
Then watch for enthusiasm and pay attention to the details. The goal seems to be to identify someone who really enjoyed and takes pride in a program they've written.