When your functional software automatically updates, introducing bugs.
The Google chrome web browser automatically updates to the latest version. This can be great when you get unexpected new, working features which add to your browsing experience, but every so often you get an update which breaks existing features. To top if off, Google don't offer the ability to roll back to a working version, so you're stuck with a semi-retarded piece of software.
Aww man, I just got 'chromed in the ass' by iTunes