Guy Kawasaki knows plenty about business innovation--but even he hasn't been immune to some major missteps.

Kawasaki, the former chief Apple evangelist and co-founder of Garage Technology Ventures, was the first speaker at the World Innovation Forum in New York City on Wednesday. His speech, "Innovation: The Art and the Spark," talked about the various ways business owners can innovate valuable and unique products and services.

Yet in one part of his presentation, Kawasaki talked about the danger of listening to “bozos” who can ruin someone’s vision by telling them something “can’t be done, shouldn’t be done, and it isn’t necessary.”

And to illustrate how dangerous this narrow thinking can be, Kawasaki talked about a bozo mistake of his own--with a $2 billion price tag.

Shortly after Yahoo was founded and had received funding from Sequoia Capital, firm partner Michael Moritz asked Kawasaki to interview to be the first CEO of the company. Kawasaki turned him down--saying that the commute involved too long a drive, and adding that he didn’t see how Yahoo, then run out of a garage, could become a business.

Oops.

Kawasaki says he now calculates that stock he would have received had he gotten the job would have been worth $2 billion.