All three of us had worked together at a previous company. I think this is important. One time, I started a company with someone I had not previously worked wi

All three of us had worked together at a previous company. I think this is important. One time, I started a company with someone I had not previously worked with, and that was a mistake. People's professional working style can be very different from their non-professional leisure style, which is why I think it's critical to have previously spent time with your cofounder in a work environment. However, that's just me. Ultimately, finding a cofounder is like finding a spouse - there's no universal, prescriptive formula short of "meet a lot of people".