RE: Failures in consumer facing user interfaces

Sean writes:

> I was at a local fast food establishment getting lunch when I found myself behind a gentleman attempting to work the self-serve soda fountain. [...] but the gentleman never clued in that the one button that was larger was “selected” and that he should then place his cup below the nozzle and press the physical dispense button.

I know the type of machine you're talking about and had the same problem with one recently. I was at a movie theatre with my sister (in Toronto) that had such machines for when you ordered pop. This no doubt sped things up at the concession stand, but also meant that there was a sizeable line up due to the decent showing for the next movie. I was attempting to be quick when I reached the machine – to avoid holding up the line – and my eyes apparently glossed over the physical button. I guess I subconsciously thought it was decorative or something since it isn't entirely intuitive that the button to actually dispense the pop is entirely separate from the interface used for selecting the pop. I pressed the desired flavour a few times to no effect before my sister reached over to push the button, cluing me into the machine's operation.

Interestingly, there was a near-identical machine at my university, which I used occasionally and never had any problems with – although I was, admittedly, never in any sort of rush. I must have forgotten how they work in the intervening years since they are not commonly used in, e.g., fast food establishments where I live.