Startup companies are susceptible to building products that don't solve real problems. Instead of solving a real problem, they solve a fictitious one. The team fabricates a target user based on their idea - even though such a user may not actually exist. Herein lies the problem: since the idea came before the problem, the problem is a byproduct of the idea.
So the problem being solved may not actually be a problem for anyone.
Mark Hurst in his book "Customers Included" argues the importance of talking to customers in order to inform product decisions. He states:
Customers want a simple, unadorned solution to their problem.
It's an oversimplified but accurate depiction of an entrepreneurs purpose. To create a solution that solves a customers problem. To get there you need to start with the customer. Instead of dreaming what if scenarios you start with a tangible problem.
Dreaming what if scenarios can be fun and inspiring, but it puts you at risk of dreaming an idea that doesn't have a tangible problem.
I recently had an idea for a tool that would store the principals that you live your life by. It's LinkedIn meets About.me meets Twitter. A digital locker of motivational quotes. But what problem is this idea solving? I formulated a persona of a tech-savvy twenty year-old who meditates and does Yoga. Even though such people exist, do they have the problem of not having a tool to store their motivational quotes? Do they need such a tool? Is this a burning problem in their lives?
Even though the idea is interesting, the idea created the problem to justify the idea.
But the customer doesn't know what they want. So you'll build something visionary that will blow their minds and make them wonder how they lived without it. The probability of getting the idea right, followed by successful marketing/sales campaigns to get the product in the hands of your target users is very low.
Your idea may solve on one of three types of problems. A nonexistent problem. A problem the customer did not know they had. And a problem a customers knows they have.
The what if blank page brainstorming approach will likely get you an idea for a nonexistent problem. To get an idea that solves one of the other two types of problems requires a more focused approach. Whether it's talking to customers, doing research, reading (a lot), you need to focus not generating an idea, but on identifying a problem.
Once you know the problem you're solving, formulate your solution.
Don't do it the other way around.