The problem with dishwashers is they don't start themselves. You have to do it. And if you are anything like me (two eyes, a nose, a mouth, 2 arms/legs, etc) you may sometimes forget to turn on the dishwasher, even if you loaded it with soap.
The main part of this deals with the fact that dishes are
heavy. Glass, pyrex, heavy-porcelain, it ll weighs down on the dishwashes. A few pressure-sensitive load-detectors placed at key points would enable the dishwasher to tell if it is full. Once it is full it:
A) starts itself, if it has soap in the soap dispenser
or B) beeps angrily at you, demanding soap
When either A or B happens, and it runs and washes the dishes, it must be reset before it runs itself again. To reset it, you just unload the dishwasher. Once empty, it registers that there aren't any dishes, and waits for the next load..
The second part deals with the soap. I sometimes forget to load in soap, and run the dishwasher without it. A simple solution to the problem of soap is to use a large portion of the top-half of the door to hold a month's supply of dishwasher soap. Since the door of a dishwasher is hollow, why not just use the space to hold and dispense soap?