Implicit features

When collecting requirements, users often forget to tell us what they take for granted - the invisibility of all that works well. Users usually focus their requests on what doesn't work. Here's a great true story a friend of mine told me years ago:

My friend had collected the requirements over an old salary processing application that was being rewritten - the original application used punched cards as a datasource, that's how old the application was! When he presented the new application for testing, the user complained about the lack of two features: defining the order of the reports and the removal of an employee from the salaries list.

"The old application didn't do that!" - he replied.

"Yes it did. Come with me to the systems room and I'll show you".

The user got the punch cards list out of the reader queue, each carrying an employee name, and showed how easily it can be reordered. "And there you go, all the reports in the application will use this order!". Oops...

"And look, if I want to remove this guy from the salary processing, all I have to do is to take his card away".

Here's implicit features for you...