The knee-jerk answer to every system problem is to find the vendor's Web site, download the code with the most recent time stamp and hope for the best. We're not exactly sure what service packs do, but we'll slather them on with a trowel.
All useful software has bugs.
And the most useful code has the most bugs. Unintended side effects grow with software complexity. No vendor is immune, and no product is too mature. Picking on Cisco for a moment, the company lists 258 defects for its 7200 line of products alone. A third of these problems exist in the IOS 12.0 release.