Introduction In their attempts to fight complex social problems, policy-makers are vulnerable to what could be called ‘the rationality trap’: assuming citizens behave rationally whereas in reality they do not – or at least not all the time. In the rational policy model (Bovens et al., 2012), three types of tools can be used to guide citizens’ behaviour: (1) judicial tools (commandments and prohibitions); (2) economic tools (financial incentives); (3) communicative tools (persuasion and warning). These tools ‘assume’ that the subjects of the policy are driven by rational motivations. In other words, classical policy instruments presuppose that people’s actions aim towards deliberatively articulated goals that are more or less stable. The emotional state of individuals, however, can be considered as one of the many reasons why people do not act in accordance with the rational model. This chapter explores the role of emotions and non-rational behaviour in a domain that until now has primarily been analysed from a rational, economic perspective, namely the housing market (see for an exception Christie et al., 2008).