The increasing excessive, automated or unaware use of smartphones calls for a better understanding and design of ‘mindful’ interactions with this device. In this 2-week study with 11 participants we focus on the influence of the operating system’s interface in inviting for ‘mindful’ or ‘mindless’ interactions. Patterns of smartphone use were studied with a standard interface for the first week, and a reconfigured interface for the second week - the reconfigured interface being designed for more intentional use. Based on the study results we formulate a set of 5 design research themes for mindful interaction, and illustrate them in a conceptual proposal.