If it works, don't update. This is why i didn't replace my XP
The problem with that thinking is that in a Enterprise Environment you have update requirements in PCI, HIPAA and SOX. Under PCI you have 30 days to apply all patches and updates from time of release to stay compliant. Not updating and then having a breach in your network could mean huge fines.
Any sufficiently advanced bug is indistinguishable from a feature. -- Rich Kulawiec