An unkown working partner increases social accountability.
Why is it easier to hit the gym at a set time each week with a workout partner than doing workouts alone? Because we feel a sense of obligation to the other person. We refer to this feeling as social accountability. And the less we actually know the other person, the more we feel socially accountable. With strangers, we will automatically make more effort to be on time. In addition, we are less likely to distract each other from work than we would amongst friends. (But of course, feel free to reach out to the other person and discuss your projects in the 10-minutes break.)