One of the most notorious features of Windows Vista was User Account Control, better known as UAC. Because of the annoyance factor that UAC presented, many Vista users chose to simply turn it off instead of dealing with the constant security warnings that it provided. User Account Control has returned in Windows 7, but it has been changed to make it more customizable. The UAC's level of sensitivity can be adjusted so that it won't go off with every program that is launched, and it can be more easily turned off if the user desires.