Tired of dealing with Vista's annoying "Windows needs your permission to continue" window each time you want to make a change in the Control Panel? It's not hard to get rid of, but before you reach for that off switch, think why it's there.
Unlike its predecessors, Vista doesn't give "administrator" users carte blanche. Instead, administrators operate in a more restrictive "standard user account" mode most of the time. Only when you make a change that supposedly affects other users on your PC (regardless of whether there are any), such as installing a new hardware driver or changing Windows Firewall settings, does Vista prompt you for your permission.
The point of this design is to block unwelcome access to the operating system and thus keep out spyware, viruses, and other malware. Of course, this newfound sanctuary comes at a cost: The UAC prompt is cumbersome, and the restrictive policies that come with it can break some software.