It takes years and years, usually a decade, to create a great startup.

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

... fire fast when it's not working. It's better for the company, it's also better for the employee.

The most common post YC failure case for the companies we fund, is they're incredibly focussed during YC on their company... and after they start doing a lot of other things. They advise companies, they go to conferences, whatever.

When lack of structure fails, it fails all at once. What works totally fine from 0-20 employees, is disastrous at 30.

In general don't start a startup you're not willing to work on for ten years.

Stay focused and don't try to do too many things at once. Care about execution quality.