For several years, I was very puzzled by one of the microwaves in our office’s cafeteria.  It had just two buttons: “Start” and “Cancel”.

Each time I wanted to use it, I sat there baffled, wondering how I was supposed to tell it how long to heat my food for.  Opening the door revealed a more familiar set of controls that allowed you to enter how long to heat the food up for, but once you had programmed it, you still needed to close the door and press the start button on the outside.  There was plenty of room on the outside of the door to place the controls there, so why had they created this cumbersome hidden control setup?

After years of puzzlement, I finally pressed the “start” button one day, just to see what would happen.  To my amazement, the microwave sprang to life and automatically started counting down on the timer for one minute.  I pressed the button again, and the timer increased to two minutes.  Another press, and it was up to three.  The “Start” button was actually an “add a minute to the timer and start” button.

Somewhere along the line, someone clearly had a brilliant insight into how people use microwaves.  99.9% of the time, people were sticking in a food item and heating it up for 1, 2, or 3 minutes.  Sure, if they wanted to, they could set the timer for 2 minutes and 53 seconds, but the fact of the matter is that nobody ever does.

Sadly, this stroke of insight was completely undone by a horrendous labeling mistake.  Rather than calling it something useful, like “+1 minute”, it just says “Start”.  Every microwaves already has a “start” button that you press after entering the amount of time you want, so it leaves the users baffled about how they were supposed to operate it.

The interfaces of most microwaves look like they were designed by engineers.  As an engineer myself, I have a soft-spot in my heart for these folks.  However, I recognize that as engineers, we are trained to think about all kinds of complicated edge cases and advanced usage scenarios.  We tend to forget that most of their users are just trying to do something simple. 

In my mind, this is why the controls of microwaves feature dozens of buttons for complex use cases like power level settings, clock configurations, automatic heating systems, and other things that a small percentage of advanced users want to do.  Heck, my “fancy” GE Profile microwave at home has buttons for setting reminders and scheduling appointments.  I cringe to think about what focus group led to that being listed in the requirements specification.

I’m as guilty as the next engineer of overthinking an interface and adding too many damned buttons onto it.  But I recognize that this is why I’m part of the engineering team, not part of product management. 

If you ever want to know why interface design needs to be a separate job from software engineering, take a look at the microwave.