There are so many skills required to be a Product Manager (can read in pervious article here).
People are an unpredictable variable and I try to at least mitigate that by using a framework to identify their main characteristics and values that you should validate through time.
The 16 Personalities
There is a study and theory that assigns people into 16 different personalities (more details). Those 16 personalities are divided into 4 groups: Analysts, Diplomats, Sentinels and Explorers.