So it's worth some real up front time to think through the long term value and the defensibility of the business.

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

... the thing we see wrong with YC apps most frequently, is that people have not thought about the market first and what people want first.

Most startups are not nearly focussed enough. They work hard...maybe, but they don't work hard on the right things.

AirBnB happened because Brian Chesky couldn't pay his rent, but did have some space.

... you can think about that for everyone you hire: will I bet the future of this company on this single hire? And that's a tough bar.

Don't let the company get distracted or excited about other things. A common mistake is that companies get excited by their own PR.