Rumination is common and has well-evidenced impacts on mental health, however, our understanding of this process is limited. Here, we used the tenants of self-determination and personality theories to explore three understudied areas: first, rumination in non-clinical populations, second, the nature and impacts of positive rumination, and third, how and why rumination differs between people. 
A convenience sample of one hundred and thirteen participants (Mage = 32.75, SD = 16.87) completed online self-report questionnaires assessing personality traits, theorised mechanisms underpinning the rumination and wellbeing relationship (i.e., psychological need satisfaction), and rumination style and duration. Participants also provided qualitative data regarding the content of their rumination, on one occasion at the end of the day. 
In line with hypotheses, significant positive relationships were identified between theoretically adaptive personality traits (e.g., conscientiousness, extroversion, and agreeableness), positive rumination styles, and need satisfaction. In contrast, maladaptive personality traits (neuroticism and covert narcissism) were associated with both negative rumination styles and need frustration. Deductive content analysis of participants’ ruminations identified causes, response strategies, and outcomes of positive and negative events. Comparative analysis of extreme adaptive and maladaptive personalities demonstrated use of more harmful and ineffective (as identified by: Skinner, Edge, Altman & Sherwood, 2003) response strategies used by maladaptive personalities.
Overall, the data reinforce the importance of capturing both positive and negative rumination, as well as focusing on how we process small, daily hassles and events. The findings highlight opportunities for future intervention and adaptation, including, importantly, the promotion of positive rumination, to promote wellbeing.