Pop the 'Why?' Stack

You should discuss...the feature and pop the why stack max 5 times (ask why recursively) until you end up with one of the following business values:

  • Protect revenue
  • Increase revenue
  • Manage cost

If you’re about to implement a feature that doesn’t support one of those values, chances are you’re about to implement a non-valuable feature. Consider tossing it altogether or pushing it down in your backlog.

- Aslak Hellesøy, creator of Cucumber

(If you follow the link, you can also read the transcript of an IRC session in which Aslak helps someone pop the "why?" stack for a "login" feature.)