Firing people is one of the worst parts of running a company. Actually in my own experience, I think it is the worst.

You'll get more support on a hard, important, project than a derivative one.

You certainly don't need to have everything figured out in the path from here to world domination.

I prefer to invest in a company that's going after a small but rapidly growing market than a big but slow growing one.

... 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.

The idea should come first, the startup should come second.

These all sounded really bad, but they turned out to be good. If they had sounded really good, there would have been too many people working on them.