Instead of trying to make this into an excuse of being humble, it should be acknowledged as a lack of a certain important trait.
Given that imposter syndrome is well-documented in our industry, it's quite possible that I've done cool things, or impressive things, but not realize that they are cool or impressive because I am in awe of the awesome developers I work with.
Combine that with most of my work being something like "I added new features in our Ember app, and fixed bugs in the UI and backend", and it often is easy to feel like the day-to-day work I do isn't awesome, even if what I am building is (IMO) pretty cool.
The interviewer should not change here, you should change to be able to convey your work and why you think its cool etc. Thats exactly what the interviewer is looking for.
Sometimes it's not about confidence. Sometimes it's about complex social dynamics and how people react to suddenly being thrown into the deep end of a domain that's completely new to them.
"Tell me about a technical challenge that won't make me feel inadequate or be difficult to follow. Don't make it too simple though because then I'll think you're an idiot."
Ah yes, just be confident. That's the ticket.
It's amazing to watch you bend over backwards to try and vilify a person who simply strives for accuracy.