... for the top twenty most valuable YC companies, all of them have at least two founders.

Most good founders that I know at any given time have a set of small overarching goals for the company that everybody in the company knows.

You can basically change everything in a startup but the market.

By the way, that's my number one piece of advice if you're going to join a startup: pick a rocket ship.

If you compromise and hire someone mediocre you will always regret it.

You also want people who are maniacally determined and that is slightly different than having a risk tolerant attitude.

Unpopular but right is what you're going for.