What differentiates the success stories from the failures is that the successful entrepreneurs had the foresight, the ability, and the tools to discover which parts of their plans were working brilliantly and which were misguided, and adapt their strategies accordingly.

I asked all of our recruiters to give me all resumes of prospective employees with their name, gender, place of origin, and age blacked out. This simple change shocked me, because I found myself interviewing different-looking candidates - even though I was 100% convinced that I was not being biased in my resume selection process.

As an entrepreneur, I knew that if my company failed, I could always try again. So I often felt that the only real risk of true financial ruin came from the possibility of a serious illness that either exceeded my insurance plans lifetime limits, or was not covered due to rescission.

This is one of the most important lessons of the scientific method: if you cannot fail, you cannot learn.

If you cannot fail, you cannot learn.

The mistake isn't releasing something bad. The mistake is to launch it and get PR people involved. You don't want people to start amping up expectations for an early version of your product. The best entrepreneurship happens in low-stakes environments where no one is paying attention, like Mark Zuckerberg's dorm room at Harvard.

The hardest part is the grueling work of constantly being wrong.