Feature creep refers to the gradual accumulation of unnecessary features in a product – a common pitfall in product development that can undermine usability, increase complexity, and alienate consumers. Gourville explains that companies often “irrationally overvalue the new” while consumers “irrationally overvalue the old”. This mismatch—what he calls the “9x effect”—means that developers believe their innovations are nine times more desirable than consumers actually perceive them to be
The bias drives teams to add extra functions, mistakenly assuming that “more features” equate to “more value.” However, consumers, anchored in the status quo, tend to perceive each added feature not as a gain but as added complexity and cost. As Gourville notes, “losses loom larger than gains,” so even small inconveniences or learning costs can outweigh perceived benefits This dynamic mirrors the endowment effect described in the article: developers, much like consumers with their existing products, overvalue the innovations they create and view their new features as essential. In turn, they expect consumers to share the same enthusiasm. Yet, as Gourville writes, executives’ “reference points shift,” and they “fall victim to the endowment effect just as consumers do”. The result is a flood of unnecessary additions—each one designed to justify the innovation’s superiority, but collectively overwhelming the user.
To avoid this trap, product managers must resist internal pressures from “eager sellers” and instead empathize with “stony buyers.” Gourville urges companies to “minimize behavior change” by creating “behaviorally compatible products” that fit seamlessly into existing habits. The success of Toyota’s Prius, for instance, came from its ability to offer new benefits without requiring consumers to change how they drive.
If a new feature cannot deliver an order-of-magnitude benefit that clearly outweighs consumer losses, it likely does not justify its inclusion. Product managers should thus ask not “Can we add this?” but “Will this meaningfully overcome the consumer’s loss aversion?” In sum, feature creep is a symptom of the psychological biases Gourville identifies: developers’ overconfidence, consumers’ inertia, and the mutual misunderstanding between them. By internalizing Gourville’s insights—recognizing the 9x gap, respecting the endowment effect, minimizing behavioral disruption—product managers can avoid cluttered products and instead design innovations that consumers genuinely value.
