I met a "Business Co-Founder" once who cornered me at an industry dinner and literally said to me with a straight face -- "very few people in the world have the product vision I have, very few people can see 10 years into the future"

The person had never run a business, never been a product manager, never built a product, could not code. I almost choked on my coffee but tried to be cordial.

Confidence is a hell of a drug.