Both as a kid and as an adult, I've encountered elevators lined up next to each other, or single ones, which have two buttons on each floor (outside of the elevator):
Pressing one of them makes it light up. Not understanding what the arrows/pointers symbolize, I always pressed both. They would stay lit until the elevator arrived. I have no idea if I made myself wait longer or caused issues for others by doing this.
As far as I can tell, there is nothing whatsoever which explains what the buttons do. No instructions of any kind. This was apparently considered so obvious that even the dumbest person could figure it out. But clearly, they had not thought about me...
To me, the most likely way in which they are meant to work is:
Pressing "up symbol" means "I want to go up", and pressing "down symbol" means "I want to go down". That is, you are just implying that you want it to arrive at your floor ASAP, but the information you input is where you want to go. Correctly telling the elevator system this information supposedly helps it perform optimally for everyone, and potentially even shortens your own wait time.
However, if that's what it means, then why am I allowed to press both buttons, which then both stay lit? Shouldn't it then disable the other button since you pressed the first? Since you can press both, that gives zero useful information to the elevator system. Unless that means that there are people standing in line who want to go up and others who want to go down... but that sounds too complex of a setup.
Another possible interpretation is:
Pressing "up symbol" means "I want the elevator to go up, stopping at my floor, because it's currently below my location", and pressing "down symbol" means "I want the elevator to go down, stopping at my floor, because it's currently above my location". Since each person can see where the elevator currently is (on a separate series of lights, above the elevator), this is quite possible, albeit perhaps slightly less likely.
So... which is it? Or does it work in some entirely different way? Am I the only person in the world who manages to get confused by those buttons?
Wouldn't the best design be to have just one button per elevator entrance which simply means "bring the elevator here ASAP"? At least that cannot be misunderstood.