You may have seen this before--it is a great comic strip on how requirements can go awry.
When you look at how product or service requirements look from each person's vantage point, it is easy to see how they can be misunderstand, misinterpreted, or misrepresented.
Getting clarity of the tire swing before we start can save a lot of wasted time, effort, and money on building contraptions that no one wanted or needs.
Get the business and technical requirements spelled out in as much detail as possible from all parties; document, document, document; and have the customer approval and sign off on these.
Build to specification, on time, and within budget and make sure it meets the operational mission needs and strategic vision of the organization.
(Source Photo: here with attribution to tamingdata.com)