Boudreaux buys Clarice a new automatic Jaguar XF
She drives the car perfectly well during the day, but at night, the car just won't move at all.
After trying to drive the car at night for a week (but without any luck), she calls the Jaguar dealers and they send out Thibodeaux, their best technician to check it out.
Thibodeaux checks the car and can't find anything wrong with it. So he asked Clarice: Are you sure you are using the right gears?
Clarice is mad now, yes: You fool, you idiot, how on earth you could ask me such a question?
I might be a blonde but I am not dumb you know!
Of course I'm using the right gears;
I use the D during the day and the N during the night.