Testing is always a critical part of any change process.  This unanticipated issue led to a much quieter morning for me and millions of other Blackberry users.

System update led to BlackBerry outage
http://www.msnbc.msn.com/id/18229224/

QUOTE: NEW YORK - BlackBerry maker Research in Motion Ltd. said an insufficiently tested software update at the company's network data center was the cause of a service outage this week that left millions of users without wireless e-mail access.

In a statement late Thursday, the company said the outage from Tuesday evening into Wednesday morning was triggered by "the introduction of a new, non-critical system routine" designed to optimize the cache, or temporary holding space, of the system that handles e-mail sent to BlackBerry users.  RIM said it didn't expect the update to impact users, "but the pre-testing of the system routine proved to be insufficient."