Recently we got a new vending machine at our office. Here is how the old machine worked.

1. You walk up to the machine.
2. You look through the glass and see what you want.
3. You insert your money, push the 3 digit code, and the desired item falls to the bottom.
4. You open the door and retrieve the item.

Here is how our new machine works. You are not going to believe me, so I have pictures to prove it.

1. Just as before, I walk up to the machine. We have yet to perfect a robot item delivery system yet, but I am sure one of the Office of the CTO robotics guys is all over it.

   

2. I look through the glass and see what I want. I've got my eyes on some Peanut M&M's. I see that the number is 502. I have no idea how much they cost. I hope I have enough cash on me.

   

3. Though there is nothing to suggest that the panel to the right is a touch screen, I have an iPad, so I might as well give it a go. I touch the screen.

   

4. Though there is only one user-interface choice, I am asked to "Make a selection" and touch the screen again. I am guessing this step is verification that I know what I want. The machine has no knowledge that I already had my eye on the Peanut M&M's. Perhaps one day AI will progress to the point of mental telepathy? I press "Make a selection."

   

5. I enter 502 which corresponds to the Peanut M&M's.

   

6. I now see that the Peanut M&M's cost $1.00. With the old vending machine, I would insert the money and be done. Here I am afforded the opportunity to purchase more items that are not good for me. So I need to touch the screen for Checkout.

   

7. I insert my dollar bill.

   

8. I get a thank you message while the machine locates item 502.

   

9. As with the old machine, the item drops into the trap below. I open the door and retrieve it.

   

That's 9 steps instead of 4. What's going on here is that the new machine handles the use case where a person wants to purchase more than one item. The old vending machine made a person buy one item at a time. My problem is that 100% of the time I only buy one item. This new machine offers functionality I do not need and complicates the functionality I do need.

User interface critique is alive in the lab.