  Hassenzahl (2008) defines User Experience (UX) as "the momentary feeling
(good or bad) while interacting with a product or service" (p. 2). Even though
this definition, or any other UX definition for that matter, do not mention
that users' experiences need to be positive, the importance of experiencing
positive emotions while interacting with a device is widely acknowledged. The
equation "better UX = more business" is the motto that determined the industry
to embrace this field, and at the same time, opened the path for the UX to go
beyond usability guidelines and the human factors studies. It is clear that, by
facilitating tasks to the users and by addressing their needs, they will be
more satisfied, more engaged, and eventually, it will have positive
consequences on the business. Nonetheless, some companies are willing to reach
their economic goals at any cost, regardless of whether the customer's feels
satisfied after obtaining what she needed. They wonder: how can we design the
user interface in order to increase the possibilities of reaching our
objectives in a much more effective way? Metrics related to purchase
conversions, user retention and engagement become the main focus of design, and
any UX research conducted is aimed at understanding the user's needs or
preferences is used for this purpose. In these cases, design is mainly aimed at
increasing the company's revenue, and companies sometimes cross the ethical
line with this goal in mind. Such a phenomenon is called Dark UX.
