Habit-forming dark patterns and how EU regulations fall short: the case of Apple’s iMessage colour-coding

Choice architecture design has become a defining feature of the digital economy, shaping how users interact with online platforms. Once designed to enhance usability, interface techniques now often exploit cognitive and emotional biases to steer behaviour – commonly known as dark patterns. While regulators increasingly recognise such practices, most legal frameworks still treat manipulation as a discrete event. This paper argues that such an event-based lens overlooks habit-forming dark patterns, which influence behaviour cumulatively through repetition, familiarity, and social reinforcement that make engagement effortless and exit costly. Within ecosystems amplified by network effects and economies of scope, these designs can entrench user loyalty and market power without overt deception. Using Apple's iMessage colour-coding to demonstrate, the paper examines how these subtler, cumulative influences challenge existing EU instruments and calls for a more coherent framework capable of addressing process-based and market-level harms.