Windows XP didn't want to shut down

Any running application on XP can veto a shutdown if it so chooses. The original intention behind this was to allow applications that were doing critical work (such as CD burning) to prevent a machine being accidentally shut down. It also gave applications the option to warn users if there was unsaved work etc. Unfortunately this behaviour has been heavily abused over the years with many apps just refusing shutdown without giving the user any explanation as to why.

It got so bad that the whole procedure has changed under Vista, applications are expected to quit immeadiately if they can, autosaving any unsaved documents into temporary files that the user can recover when the system restarts. If the shutdown is being performed interactively, then apps such as CD burners still have the option of blocking shutdown but Windows clearly shows the user which applications are doing so. If the shutdown occurs because of a hardware event like a laptop lid being closed, applications are shut down regardless of whether or not they want to block shutdown (the assumption being that if the user still cared about the CD burning, they wouldn't be shutting the lid).