Excerption: Agile Methodologies ask…

If design is good, why not make it everyone's job? (Refactoring)

If simplicity is good, why not use the simplest design that supports the currently desired functionality? (Simple design)

If architecture is good, why not have everyone work at defining and refining the architecture continuously? (Metaphor)

If short iterations are good, why not make iterations really short (hours and days) instead of weeks and months? (Short iterations & planning games)

If requirements, design, and code reviews are good, why not do it all the time? (Pair programming)

If testing is good, why not do it all the time… even customers? (Continuous unit and functional testing)

If integration testing is good, why not do it several times a day? (Continuous integration)