If someone is choosing between joining McKinsey or your startup it's very unlikely they're going to work out at the startup.

You only get points when you make something the market wants. So if you work really hard on the wrong things, no one will care.

... 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.

Cofounder relationships are among the most important in the entire company.

A related advantage of mission oriented ideas, is that you yourself will be dedicated to them.

The tenth social network, and limited only to college students with no money, also terrible. Myspace had won.

No growth hack, brilliant marketing idea, or sales team can save you long term if you don't have a sufficiently good product.