I have been driving the same car for over ten years now. I've pretty well got it down cold. I can even reset the clock, without needing to consult the owner's manual, in about a minute while keeping one eye on the road. (Now there's an unexpected downside to the digital era...)
But heaven forbid I ever vary my shutdown routine one little bit...
See, the Zed Drei has the classic Detroit-style "organ stop" headlight knob on the dash to the left of the wheel: Pull out one click for parking lights, two clicks for headlights, and twist to dim or brighten the instrument panel. When I get out of the car normally, I operate this switch with my left hand, but when I'm un-assing the car in a hurry, I'll pull the keys from the ignition with my right hand while my left is operating the door, and hit the headlight knob with my right hand in passing on the way out.
Apparently, BMW considers this to be the Worst Thing You Can Do in this automobile, because, should you commit the grievous error of removing the key from the ignition while the lights are on, rather than a warning beep or chime, the car lets out a noise used in science fiction movies to signal a warp core breach. It would probably cause a U.S. Navy veteran to look around for the button to SCRAM the reactor. It triggers, even after a decade, the same reflexive spinal-level twitch you'd get from the sound of a running Husqvarna being lobbed into a playpen.
I hate that noise. Which I guess I'm supposed to, since I believe you would need to be deaf to leave the lights on in this car.