A Blonde buys a new Automatic sports car. She drives the car perfectly well during the day, but at night the car just won't move at all. She tries driving the car at night for a week but still no luck. She then furiously calls the dealer and they send out a technician to her.
The technician asks "M'am, are you sure you are using the right gears?"
Full of anger she replies:
"You fool, idiot man, how you could ask such a question, I'm not stupid!!
I use "D" for the Day and "N" for the Night..."