Dammit a good article...

.. by Alistair Cockburn. When this guy is on, he writes really, really well.

http://alistair.cockburn.us/crystal/articles/aih/areiterationshazardous.htm

Good example of not getting caught up in the hype of XP. Remain focused on the end goal and make your development process work around that. Don't make the process the end goal.