Agile work actually requires a lot of discipline. One place that a team's discipline (or lack thereof) shows up is in the basic rhythms of their work: Release, Iteration, Day, Story/Feature.
Various methodologies put different activities in place to mark the beginning/end of these cycles. One key activity is the Retrospective - in fact, continuous integration, when practiced frequently during the day, may be seen as the most atomic form of retrospective, and these increase in scale through story acceptance, daily stand-ups, and iteration and release retrospectives.
When things are going smoothly, the benefits of using these patterns may not be obvious, and it's easy to let them slip or disappear. When such basics are discarded, soon enough problems will surface. When they do, it's easy to make the mistake of fashioning creative bandaids, rather than returning to the roots of the methodology to see where the basic practices have been omitted or changed to the point that their balancing effect is no longer operational.
Three articles in the latest online edition of Agile Journal, focused on metrics, look at these rhythms as a key aspect of Agile practice:
Iteration and Release Retrospectives: The Natural Rhythm for Agile
5 C's of Agile Project Management,
which are: Courage, Context, Course, Cadence, and Cost
Update, July 2, 2006: For an example of rhythm in action, check out Erich Gamma's keynote at JavaOne, where he described in detail the multiple rhythms of development at Eclipse.org. A video of the talk is also available.