Service organizations are struggling to understand and change behaviour since it is complex, dynamic, multidimensional and very often not considered to be rational. Human behaviour is a key component in services, as the interaction between a user and touchpoints determines the overall performance and value. Increasingly, service organizations aim to influence or change behaviours. Livework Studio, one of the leading service design agencies in the world, wants to incorporate the knowledge of behavioural economics into their practice to fundamentally understand and guide customer behaviour. The main objective of this project was to develop a structured design approach that supports Livework designers to incorporate behavioural economics theory into their process.  An extensive research was conducted to generate insights on how Livework can use the behavioural economics theory in the design process of services. The insights gained throughout the project were integrated into a design approach and toolkit. The approach is focused on influencing behaviour by getting the customer in the right mindset at the right time. In this approach two types of behavioural interventions are combined across a customer journey to either speed up or slow down the user’s momentum. These interventions do not only facilitate automatic and fast thinking (such as nudging) but can, when necessary, switch customers to the conscious state. People can be prompted by rational override interventions to switch to the conscious state. Rational overrides are micro moments of friction that can be used to disrupt mindless automatic interactions, prompt moments of reflection and increase conscious decision making. Not all service interactions require the speed and usability of a frictionless experience. Some situations require users to slow down, focus on the decision at hand and understand the options that they have. In these situations, friction is not bad, it is necessary. This research identified nine strategies that can switch people to reflective and conscious thinking.