The quote of the day comes from Jeff Bezos: “you can’t put into a spreadsheet how people are going to behave around a new product.” 


I believe that our over-reliance on proforma tools is caused by our fear of failure. They are either attempts to control the future, or to predict it in order to prevent failure.


But you really can't see how a potential product or service will work unless you can watch a customer, in a natural purchasing setting, decide whether or not to purchase the product. If it doesn't work, then try adjusting the value proposition by changing the price, distribution method, or how you advertise. If it still doesn't work, then scrap the product or service rather than launching it on a full scale. If you don't launch it, then move on to the next idea.