One issue that I commonly confront as a programmer and analyst is the perception by business folk that requirements are self-evident.

Folks will say something like "I need a website for my business" or "I need a software application" then ask how long it will take and how much it will cost. They often don't realize that a more information, a lot more information is required before any kind of estimate can even be hazarded at.

Compounding the problem is that the business person is often so busy managing day to day details of their business that they don't feel that they have time to answer a bunch of seemingly generic questions. I like to have a robust view of the segment of the business into which the application will fit, so I can plan for efficiency and scability and avoid duplicating existing functionality.

Small business people tend to be pretty guarded about this information though. They don't want to tell you about the internal structure of their business unless they feel that you have a pressing need to know, and when you ask about something that is not directly related to the process that they want automated then they can be vague and evasive.

It helps a lot if you can talk face-to-face with the business person, or at least arrange for telephone conversations. While I really like email as I can save and search it, I find that business folks often to not take the time to provide complete answers to questions phrased in emails.