Re:Depends (Score 0)

Agreed - requirements specs and functional specs are often written by business analysts, with no reference to the end users. It's absolutely vital to involve users before the requirements phase finishes, and the design work starts. And, of course, those same users can be involved in all the testing phases, but particularly User Acceptance Testing (UAT). If what you implement sucks, you may all get a pat on the back, but will have utterly failed to fulfill the business need.