There are no facts inside the building so get the hell outside.

The world is run by those who show up not those who wait to be asked.

Using the Product Development Waterfall diagram for Customer Development activities is like using a clock to tell the temperature. They both measure something, but not the thing you wanted.

Unless you have tested the assumptions in your business model first, outside the building, your business plan is just creative writing.

No Plan Survives First Contact With Customers

A startup is a temporary organization designed to search for a repeatable and scalable business model.

Business plans are the tool existing companies use for execution. They are the wrong tool to search for a business model.