Krishna lists seven types of people we encounter: well-wishers, friends, enemies, the indifferent, mediators, those who hold grudges, and relatives. Among all of these — and even among the virtuous and the wrongdoers — the person who maintains sama-buddhi, an even mind, stands apart as exceptional.
This is one of the hardest teachings to practise. The natural human reflex is to draw close to friends and keep distance from enemies. Krishna is not saying to ignore these differences. He is pointing to something beyond reflex — a steady inner lens that does not warp based on who stands before you.
A doctor treating patients in an emergency room does not ask whether the person on the stretcher is a friend or a stranger. The attention given is the same. That professional equanimity, extended to all of life, is what Krishna calls sama-buddhi.