For example, a button that seems visibly pressed (even lights up! Maybe there's even audio or haptic feedback!) but once you release, nothing actually happens because you were supposed to press it or hold it down for slightly longer.

This even happens with physical controls: in some elevators you can press a floor button such that it lights up momentarily, and even beeps, and yet the elevator doesn't register the command and you have to press again, longer.

[–] Rednax@lemmy.world 9 points 2 days ago* (last edited 2 days ago)

I have this experience with a certain type of pedestrian traffic light "button".

I quote button, because nothing physically moves when you press it. I'm not sure if it registers pressure or heat, but you don't even feel anything move when you press it.

Usually when you press the button, a red text lights up on the button, telling you to wait. This text gives you feedback that the button registered your press, and the traffic light will schedule a green light for you.

However, sometimes you didn't press hard enough, and the text doesn't light up. Simple solution: press harder.

But there is a scenario where it doesn't matter how hard you press, the button won't light up. You keep staring at it, while slamming the damn thing with the fury of a Hulk wealding Mjolnir. Still, nothing lights up. The reason: the light instantly went green, so it never needed to light up the text telling you to wait. And all that time slamming your fist on the button, could have been spend crossing the intersection. Instead you have been standing there, looking like a drunk person having a fistfight with an inanimate object.

[–] xthexder@l.sw0.com 5 points 2 days ago

I've actually noticed this exact thing with elevators before... I was kind of amazed the beep and light were hooked up completely independently from the actual floor selection logic.
It sort of makes sense that the light in the button would just be hooked directly up to the button contacts. The computer would then be polling the buttons separately and it's possible to miss a button press... These sorts of buttons shouldn't need a debounce period since pressing any of them a second time doesn't do anything. If the buttons were interrupt based, this probably wouldn't happen.