Delightful engineering

I usually relate delight operating a software with usability or functionality.

A Delightful software is more easily sold. A Demo or a talk featuring nice usability features is much more successful, like:
-the software "guessing" what the user would do next and provide shortcuts; remove redundancy often cuts several useless steps in wizards, for example; according to context, do not provide useless options:
-a software that is self-explained, and makes the user feel a genius, instead of making him feel stupid;
-Functionalities presented as bonus; the user is surprised by capabilities that were not intended at first, but tooltips are telling him they exist and are easily accessible.

The problem here is that delightful features often become standards. If they are good and useful features, people will expect for them, and maybe submit defects when the "delightful features" are not present. Then the term "delight" often evolves to "good design".

Just trying to resume, I think good "engineering" has the implicit capability of creating delight, even if it is not it's purpose. The world is full of this, just like good furniture, cars, engines, planes, architecture, music, art...