In my view, it's irreverence, foolish confidence and naivety combined with persistence, open mindedness and a continual ability to learn that created Facebook, Google, Yahoo, eBay, Microsoft, Apple, Juniper, AOL, Sun Microsystems and others.
If you're going to build something, don't build on land someone else already owns. You want your own land, your own domain, your own sovereignty. Trouble is, so much of the choice land - the land where all the people are - is already owned by someone else: By Google, Facebook, Twitter, LinkedIn, Yahoo, and Apple (in apps, anyway).