Vending machine is now ubiquitous everywhere in almost every cities in the world, it is convenient, it saves labor force and it is accessible for everyone. In my case, I am talking about a vending machine that sells drinks. When you are thirsty and want to have some refreshment, just simply select your drink by pressing the button below the displayed one, and then the machine will let you know how much do you have to pay, after inserting the right amount of cash or sliding the credit/debit card, the drink will come out to the tray at the button of the machine. People are fluent on using those machine, since the process is basically select and pay, but saying that it does not mean that there are literally no difficulties at all for some people to use. I have seen the machine could not recognize the bill and keep sending them out instead of accepting it, and also the drinks sometimes get stuck in between the tray and the display rack which leads to the customer is not able to get what they have paid for. Despite the process of getting the payment done takes the most time (half to one minutes), If the transaction goes through, it would approximately take about 1-2 minutes to get the whole process done, and if the case is either the machine cannot recognize the bill or the drinks can not come out, it might take a lot more than just 2-3 minutes or the worse case – the process is never completed (customer cannot get the drink).
According to Crawford, a good interactive process requires a part of input, and a part of processing, and a part of output, so we might have three cases for the vending machine: one is fully interactive, one has problem on the processing part, and one has problem on the output part. Being fully interactive means the customers conveniently paid and get the drink, each three parts of the interactive process is successful. The case that the machine cannot recognize the bill means there is something wrong with the processing part, without a good processing the machine cannot even operate the next step of “output”, so it keep requesting a “try again” on the payment step. Lastly, the case of the merchant got stuck in-between means the output part is having a issue, although the first two parts are successful, without the last success in the part of output does not complete the circle of interaction.