You get in the elevator and press P3 to go to parking level 3. Then you remember, wait, I'm on level 4, so you press P4. But the elevator still stops on level 3. Why isn't there a way to tell the elevator that you changed your mind?
Or you press the button to call for the elevator to go up when you really want to go down. So, an elevator full of people going up stops and opens its door and lets those people have a look at you while you wait for an elevator that is going down. Why isn't there a way to tell the elevator that you changed your mind?
No big deal, except that it causes a few people a minor annoyance once in awhile. Multiply this by the number of elevators in the world, though, and you have a huge cost in annoyance because there is no way to tell an elevator that you have changed your mind.
I believe that what I have described is true of all elevators. Correct me if I'm wrong.
The elevators that I have to deal with every day are stubborn in another way that I've not seen before. If you've called for an elevator to go down and one stops that is going up, chances are you'll climb aboard. You then press the button of a lower floor and it won't take it. The light won't come on at all. You have to wait until it has gone up to the highest floor it has decided it is going to go to, and then press the button for the (now much) lower floor. Who designs the software that controls "my" elevators? Will you please explain, what were you thinking?