Extreme Programming Pitfalls

I am starting this page because I did not find a page that have that kind of subjects... If you do please, let know everybody here!

Potential pitfalls:

ImplementAllExtremeProgrammingPracticesAtOnce?. This is our experience. Compound with the fact that only one person had some experience (an immersion). And the fact that all the practices were not well understood. Not enough process thinking and reflexion regularly... Even if everybody involved was 100% percent willing to try! So do if you do it, do not do it like that! Take your time! Explain things! Do a pet project with ExtremeProgramming!
Alternatively, starting with TooManyPeople on the team. I think you can do the full thing (HotTurkey? ?) if there are only a few keen people and you're prepared to accept that it will take a while to get working.
BlowingTheFirstIteration?. I know of first iterations on two entirely separate projects where the number of ideal days of features delivered on the first iteration was near zero. For solution and hints, see Planning XP by Kent Beck. Draft available on XpMailingList.