Actually it was a good question but you gave a really stupid answer.
Letting cars warm up is only a good tip for carburated engines, since they ran like shit when cold and it wasn't recommended to drive with the choke activated.
With fuel injection, the best thing to do is let it run for about 10 seconds, and drive off, keeping the rpms low and driving smoothly until the engine reaches operating temperatures.
Letting a fuel injected motor run at idle while cold just wastes fuel and actually increase wear and tear, since most of the wear actually occurs when the motor is cold.