Product design should factor for human forgetfulness where possible.
This is a picture of the detergent tray from a leading brand, top-loading washing machine.
The hole in the tray is where detergent, mixed with water, drips into the drum during a wash cycle.
However, when the tray is opened to fill detergent, you notice it slopes downward.
This is understandable from a manufacturer’s perspective, the reason for the downward slope of the open tray intended to prevent any liquid or diluted detergent dripping into the drum before the cycle has begun.
However, from the user’s perspective, it also means that if a user forgets to shut the tray, it will fill with water, but mostly likely won’t drip through the outlet, as you can see in this case where, shortly after starting the cycle, it was realized and shut.
And forgetting to close the tray can be a very likely possibility in the hurried world we live in. It would involve an extra wash cycle after one realizes. And more water wasted, to get the job done.
A less desirable workaround solution could involve a sensor check that alerts the user of an open tray.
A intuitive workaround could be where the tray tilts forward (instead of backward), and the outlet is placed on the lower end, and only opens during a cycle and not before. So as not to inconvenience the user.
After all, aren’t machines supposed to be designed to make human lives more efficient?