Steve Yegge, in an entertaining rant
“Self-professed experts will tell you that requirements gathering is the most critical part of the project, because if you get it wrong, then all the rest of your work goes towards building the wrong thing. This is sooooort of true, in a skewed way, but it's not the complete picture.
“The problem with this view is that requirements gathering basically never works. How many times have you seen a focus group gather requirements from customers, then the product team builds the product, and you show it to your customers and they sing: 'Joy! This is exactly what we wanted! You understood me perfectly! I'll buy 500 of them immediately!' And the sun shines and the grass greens and birds chirp and end-credit music plays.
“That never happens. What really happens is this: the focus group asks a bunch of questions; the customers have no frigging clue what they want, and they say contradictory things and change the subject all the time, and the focus group argues a lot about what the customers really meant. Then the product team says, 'We can't build this, not on our budget,' and a negotiation process happens during which the product mutates in various unpleasant ways. Then, assuming the project doesn't fail, they show a demo to the original customers, who say: 'This is utterly lame. Yuck!' Heck, even if you build exactly what the customer asked for, they'll say: 'Uh, yeah, I asked for that, but now that I see it, I clearly wanted something else.'”