The book argues very strongly for functional design and design that makes usage obvious. “The way you use a thing should be encoded in the way the thing is, not in a manual”. I’ve been told there’s a follow up that concedes some of this and argues for emotional design. Something a long the lines of “this thing doesn’t need this handle, but it makes the thing feel manageable and less intimidating”.
My biggest eye opener, though, was the idea of designing for display in the store versus usage at home.
An updated example for me is the iPhone. It has premium materials that are assembled with tiny tolerances and has a very nice feel in the hand. But once you’ve been impressed by these in the store and you buy it, you slap on a $5 cover and never enjoy the premium materials and physical design.
The reasonable thing would be to have the phone shell-less and with interchangeable covers, like an old Nokia phone, but that is not nice in the show room.