The same reason that "what's your biggest weakness" is such a stereotypical interview question. It's all about stories. If you can prove you're the best with

The same reason that "what's your biggest weakness" is such a stereotypical interview question. It's all about stories. If you can prove you're the best with math or with certifications or whatever, that is only a protection for yourself. But if you have a good story that is a protection for whoever you tell the story to. What's your biggest weakness is all about your ability to tell a good story about a failure that you're responsible for. Because if you have a good story then the person responsible for you can retell the story to the people that they answer to. Yeah, Joe messed up big time and then left the company and I was responsible for him, but listen to this great story that he told me about why everything was going to work. Clearly this failure was from external forces that shouldn't be held against me. Anyone else would have failed; it was inevitable. Desperation isn't a good story for anyone. Yeah, I left Joe in charge. And he told me that he knew what he was doing. But he also seemed really desperate (and everyone could tell), like he would say whatever he had to in order to get the job. Yeah, this is clearly all my fault and I should probably be fired too.