I like the Microsoft Fiction:
And then they used Microsoft’s most popular products to produce what they thought was a business plan. But it actually was a kind of fiction built in three chapters: an Excel spreadsheet with sophisticated analyses showing breathtaking financial potential, a PowerPoint document blending facts and figures with compelling videos and pictures, and a Word document summarizing all of it in prose so lucid Malcolm Gladwell would shed a tear.But why Mr. Gladwell?
Key question to ask:
“Who is your first customer?”I would combine this with Steve Blank' "get out the building". Spending too much time with the imaginary customers is, a work of fiction.