The adoption of design fiction into design research has recently been expanding within the HCI community. Design fiction workshops have fruitfully facilitated users and researchers discussing and creating future technologies by exposing differing viewpoints. Yet, most scholarship focuses on the ostensibly successful outputs of these workshops. It remains unclear exactly what sort of interaction dynamics are instigated by design fiction in collaborative design. How might design fiction affect what we consider in design, and how is this reflected in the ensuing design? To fill this gap, our study examines design fictions across five workshops where diverse participants created futuristic autobiographies, a method to elicit values, and built diegetic prototypes both individually and collaboratively. We detail their design processes and unpack three kinds of soft conflicts that arose between participants and allowed them to bring up and discuss differing values regarding technology in society. Reflecting on our workshops, we discuss their implications on how one might employ design fiction in collaborative design.