One of the most basic conundrums in computer security is the constant trade-off between security and usability. At the end of the day, if security is too complicated to use, then it simply won’t be used. Even if a feature offers a good level of security protections, if it is complicated or has poor usability it will likely be disabled by the end-user or network administrator, which doesn’t benefit anyone. The same issue with safety and security exists in the physical world. I remember when car alarms were first available (as an aftermarket product) — you had to remember to set the alarm after you locked your car and half the time people forgot. Today, many cars come with alarms from the factory and the task of setting the alarm is usually just part of locking the car — and as a result, alarms get set.
Microsoft, Windows Vista