I think the fundamental issue here is that PG tends to interview from an engineer's perspective. For your business, you should absolutely speak to customers. F

I think the fundamental issue here is that PG tends to interview from an engineer's perspective. For your business, you should absolutely speak to customers. For an interview with YC, you should absolutely speak to the interviewers (PG, et al), who, in this case, happen to think like engineers. The language you use should change according to your audience.