@jjg Automobiles are a good example. They're quite expensive, and they're mostly black boxes.
End users are at the mercy of the mechanics. Very few people can work on a modern car.
My boss once showed up with a small plastic square with an antenna on it she found behind her rear view mirror. We researched and found dealerships are hiding RFID tags on cars so they can greet people by name.
The computer equivalent is probably being a windows 10 user. (Trading money & privacy for ease of use)