There seem to be at least two XP-relevant challenges in the big bug situation as it stands in the first week of Y2K:
1. the apparent triumph of unit testing on a global scale despite the fact that by all accounts it was very incomplete - see YtwokUnitTestingTriumph - how come?
2. the lack of reliable, understandable feedback on how well y2k remediation was going meant that not just the general public but political leaders (judging from their greatly expanding budgets and pretty extreme contingency plans) just didn't have a proper basis for their planning.
Now if all our systems worldwide had been developed with XP what difference would this have made to the way this all played out?
I'm still in the mood for slightly tricky questions, sorry.
It would have been The End Of The World As We Know It. --RonJeffries
But I feel fine.