For all the rationale underpinning the field and for all the careful research and reasoning that shores up every new initiative, there remains an oft-overlooked truth in UX design. This truth is that UX design is as much ruled by fashion as it is function.
Users are subject to fads. Whims, design novelties and the latest fashions heavily influence the direction of the websites and products we consume. While this is by no means unnatural, it does mean that trends can toy with usability.