Some unlearning to do

I´ve been involved in building IT systems for businesses for over 13 years and, ever since my first job as a consultant at Andersen Consulting, now Accenture, I have been told the way to build computer systems is as follows: First, we in IT ask the business to identify its requirements. When we say this, we mean we would like the customer to write down a requirements document. This is meant to capture your need and is the ´why´ behind the system. In theory, any system that addresses these requirements will be fit for purpose.