My toaster oven. Top dial when in the ‘off’ position means oven is off, but toaster is on. The bottom two individually control toast versus oven.

Many a time I have left the toaster thinking it was toasting, when it was in oven position, or vice versa. The toaster ticks, but I return to find no heat, no ready food.

In software each interface should DOTW: “Do One Thing Well”. The more functions any element of an interface carries out, the less likely it is do any of them well.