Here is my list of 3 qualities: 1. Emotional Maturity - startups are super stressful, you need someone who can be a steady voice of reason. 2. Relentless - so

Here is my list of 3 qualities: 1. Emotional Maturity - startups are super stressful, you need someone who can be a steady voice of reason. 2. Relentless - someone who is stubborn and never gives up. 3. Complementary - someone who can fill in the blanks vis-a-vis your skills (tech/business/sales/..)