First of, thanks for being part of YC and making it such a great place. I've never been there, but the whole spirit is healthy and that I very much appreciate.

>I looked at qualities of the applicants my cofounders couldn't see. Did they seem earnest? Were they determined? Were they flexible-minded? And most importantly, what was the relationship between the cofounders like?

I second this. People who say soft skills are dead or unnecessary are wrong in my opinion. Of course, software is software and hardware is hardware. But how does it get there? And where does it go from there? People help people and being nice to each other is not only more beautiful, but also leads to higher productivity in my experience. Having more empathy for your co-founders, employees and investors goes a long way.