To me, the biggest ugly side of UX is Dark Patterns, which are tricks used in interaction design to manipulate you into making decisions against your best interest.
UX is about problem solving, creating efficiencies, and generally making the world a better place. As UXers, we are the user’s last line of defense against poor or malicious designs. Dark Patterns are the antithesis of everything I believe UX to stand for.
Not all Dark Patterns are created on purpose. Often they are the result of a toxic combination of business requirements and bottom-line-thinking that persuades designers they are working in the users’ best interests. However, there are interaction designers that specialize in the creation and implementation of Dark Pattern designs.
UXers are inherently in a rough spot as they need to work in the best interest of everyone (both the business and users) - and this often creates a conflict of interest. As UX professionals, we need to stand for ethical design principles and work against those who would use the foundation of our practices against the public in general. This will always be a daunting, painful, and unpleasant task, but I’m convinced it’s a battle we can win if we stand together.