Christopher Cummings' latest entertaining and insightful post is worth reading:

Think about the last time a salesperson at a retail establishment asked what you were looking for. How honest was your answer? And how

Exactly. Product teams often don't realize how misleading information coming straight from customers can be:

• They see the conversation as part of an ongoing negotiation with you, the vendor. This bigger context shapes what they say, and how they say it.
• You're dealing with middlemen. Sure, members of the IT department has a wish list, but on many issues, they're really fronting for business users who want something from you. How well they're representing this Silent Majority is anyone's guess.
• They're an unrepresentative sample. Let's be honest: the customers to whom you speak, or with whom you'd rather speak, are not the same as all your customers. You lean towards the people who are easy to work with, who understand you clearly, and who can speak the language of releases and features that you understand. That's a pretty skewed sample, and it's even further from the population of all people who might be your customer.

In other words, the traditional sources of product requirements are inadequate. Even the one that seems on the surface to be the most trustworthy, the face-to-face meeting, can be incredibly misleading.

And you often have yourself, Dear Vendor, to blame. You choose to be deceived. You get into these conversations with your own agenda--the boffo feature for which you're seeking validation, the workaround that you want them to use, the argument you just had with a co-worker about a design decision that you'd like to win, if only this customer would agree with you. You want the customer to tell you lies.

There are ways out of this trap, which is why I wrote that document about the Web 2.0 sources of product requirements that I keep talking about (and will be published soon, honest!). However, you have to want to face the hard truths of what you don't know, you might not initially understand, and in some cases, you may not want to hear.

[Cross-posted at The Heretech, where I write things that don't appear here!]