Microsoft: We Created UAC To Annoy Users
Finally, the truth has been said. During RSA Conference, David Cross, a product unit manager at Microsoft acknowledged that one of the most annoying Windows Vista’s feature, User Account Control (UAC), was designed especially with this purpose: to annoy users.

"The reason we put UAC into the (Vista) platform was to annoy users-I'm serious," said Cross, according to CNET News. "Most users had administrator privileges on previous Windows systems and most applications needed administrator privileges to install or run."

During his speech, David Cross, who was directly implicated in creating the UAC, explained also that Microsoft hoped to encourage the software makers to make their applications more secure. In case an application is considered insecure or it tries to make certain major changes to Windows subsystem, an UAC prompt will ask the user if he really wants to go further.

In addition, the UAC prompts are displayed every time a user tries to install/uninstall an application and in the case of simple operations, such as accessing device manager.

Microsoft hoped that the UAC would discourage the users to make unnecessary modifications or tweaking the system.

Also, David Cross noted that 88 percent of the users opted not to turn off the UAC system,

"It's a myth that users click 'yes,' 'yes,' 'yes,' 'yes,'" said Cross. "Seven percent of all prompts are canceled. Users are not just saying 'yes.'"