When one thinks of it, what is one of the most useful things one has ever found in an automobile, and one of the most irritating things?
I'm not talking about anything major--such as "an engine that runs"--but just assuming the automobile operates okay, no problems.
Demonic Underwear mentioned something that one doesn't see any more, and one wonders why it's not the case.
In the old days, there was a button on the upper-left hand side underneath the dashboard, that one pushed with his left foot whenever he wanted to brighten or dim his headlights.
Nowadays they put the light-changer on the steering column, and one doesn't know if he's going to do something with the lights, or send the windshield-wipers flipping.
That was a great idea, this button-on-the-floor thing.
On the flip side of the coin, I personally (which means it's something that probably doesn't bother anyone else a whit) get irritated at inside rear-view mirrors, especially since the vehicle has two perfectly-good rear-view mirrors outside, on the two opposite front doors.
In fact, after buying a vehicle, I've always taken the interior rear-view mirror off.