You Shouldn't Build What Your Client Wants
At least, you probably shouldn't, anyway. Most of the time, they won't represent the majority of users, or even any of the users. This happens in pretty much every field of software:
- In-house software is usually commissioned by the IT department, but will be used by sales, engineers, finance, and other departments.
- Commercial software is usually driven by a product manager but will be sold to thousands (or more) of people. Even where you have a dedicated customer representative, they represent only one of many users. And, as with in-house software, the "representative" may still not be the ultimate user of the application.
- Even in a case where you're building bespoke software for a small team of people who are involved in the decision-making, a disproportionate number of suggestions will come from the more senior or more vocal users; with the worst case being that specific requests get filtered through the...