Although there are times when success is impossible regardless of sales or technical ability (bad economy, market forces, etc.) - how do look for a cofounder that'll work well with you during both the best and worst of times?
The goal is to win in decent or better times, so I optimize for that. And honestly, keeping it professional removes the emotional overhead of a deeper relationship. I don't need to worry about his feelings nor he mine, we just need to succeed in our domains.
This isn't a high school cafeteria, it's a job and a mission. I'm not going to choose based on intuition or friendliness, I'm going to pair up to win.
It's worth noting that as a "diverse" founder, finding someone "like me" who I "click with" and shares my views and narrative probably isn't going to happen.