We built an automated dialogue system whose style of interaction can be varied along the three dimensions of Humour, Relationship Maintenance and Personality Matching. We then ran a longitudinal experiment which investigated manipulations of these three dimensions. We explored the interaction of these separate dimensions on user perception of the system using a controlled study design. We showed a strong positive effect for the use of Humour and Relationship Maintenance, while the use of Personality Matching raised a number of questions which need further investigation.