Seems like being able to not see the holes in your own ideas, believing your own ideas are infallible i.e. narcissism as mentioned below, are very valuable traits in a founder, at least in certain phases. To this day, I still don't get why WeWork is a thing, but it just shows me that the whole system can be hacked given enough levels of self-delusion. And often times not for the better. I mean, people mentioned in religious writings are just like us, all the same, except their headspace is somewhere far different than the average man, and their responses to external stimuli end up being completely different or uninfluenced. A bit of reality distortion field, if you will. There is certainly a phase in the beginning of founding a company where few people will believe in your idea except yourself. And sometimes maybe those beliefs need to be a bit irrational as a defense until they gain traction in reality.
Projecting a little bit here, but, I personally am the opposite, always seeing holes in everything about what I think, what I know, shooting myself down all too quickly, such that a lot of my interactions with other people seem to end up with them sympathizing for my lack of confidence but glad to see me being honest. Sometimes, I'd wish to just be a bit more of the opposite.