When a customer says to you, "we need the system to ...", they are generally referring to "features" and not "user stories". A lot of Business Analysts and Functional Consultants hear the words "need to ..." and instantly equate that to a "user story" when it is not.
Why is it a "feature", not a "user story"?
You can think of a "feature" as a workflow drawing, or swim-lane diagram. "Features" have steps along the way. Each one of those steps is a "user story" with "tasks" that a Developer must configure. When customers tell you their need, most times that need involves many steps along a path to get to the end result: so it is a "feature".
Why the mix up with a "user story"?
The general format for a "user story" is as follows: "As a (job role), I need to (list the requirement here) because (reason the requirement exists)." Because the "user story" has the words "need to" or "want to" in the format that we write them down and the fact that most customers say, "I need to have the system do ...", people equate the requirement to a "user story". Just because someone says the words "need to" does not make their statement a "user story". Again, if what they ask for has steps, then it is a "feature".
Example ...
Customer says, "I need to do spell checking in Swahili." This is a "feature", not a "user story". The steps might include opening the spell checker, clicking the "language" button, and then selecting "Swahili". Each one of those steps is a "user story". A Developer would need to do a task or multiple tasks to enable each step, "user story", along the way.
Happy software engineering.