Well, the fridge needs to be opened, closed, has inner compartments, you need to be able to regulate the temperature, possibly to let the user know the fridge i

Well, the fridge needs to be opened, closed, has inner compartments, you need to be able to regulate the temperature, possibly to let the user know the fridge is running/which temperature is inside... all this happens in the kitchen, possibly with dirty hands, or with wet hands, or while you're holdin ga handful of things... that's all UX-related aspects. The Design of Everyday Things, by Donald Norman, had a nice example of how even the wheels for regulating the temperature can be very confusing (and indeed, in basic fridges you don't regulate the temperature, you set a number on the scrollwheel e.g. between 1-7. But is 7 a higher temperature or higher cooling power?).