As an entrepreneur, it is all too easy to fall in love with your solution and be blinded to the reality of the market that you are trying to win over. Entrepreneurs should love the problem that they are solving more than the solution that they are bringing.
You must really care about the problem. You must really feel the pain of the problem. Then you will be totally wired into your prospective customers. You will see what they see and feel what they feel. This will ensure that there is no ambiguity around defining these core customers. It will also give you a natural advantage over competitors. This is critical because start-ups only work if they find customers who want what they are offering. If no-one is buying then you need to go back to the drawing board.
If you focus on the problem, it will also make it much easier to know which features matter to your product or service and which ones don’t. Constant re-evaluation of the backlog is critical to scaling quickly. If the company is waylaid by unnecessary diversions because there are too many customers competing for different needs then it will fail.