Absolutely, and mirrors my experience. It seems the more the stress test shows big flaws in the idea, the more the founders want to retrench down to "you just

Absolutely, and mirrors my experience. It seems the more the stress test shows big flaws in the idea, the more the founders want to retrench down to "you just don't understand how great our idea is and how infallible we are". At some level, it's the fundamental nature of entrepreneurship to soldier on when everyone counts you out, but more often than not, fundamentals are fundamentals and maybe you should pay attention to them.