The EcoFriends application was developed as an attempt tosupport grocery shopping adjusted to vegetables’seasonality through a performative approach to interactionand interactive applications. The design aimed at criticalreflection and inspiration among users, rather thanachieving a certain kind of persuasion. This guided thepractical design to be modelled around open-endednessand social voices to challenge ideas and points of view. Weargue that research addressing design for interactions aboutvalue-laden concepts such as sustainable action need tofind ways of supporting various knowledge discourses, bydistinguishing between performative and representationaltechnologies. The approach allowed us to identify anumber of design challenges regarding interactivetechnology and interaction design in relation to aspects ofknowledge and truth, trust, negotiation and responsibility.