Rabbi Yossi Hakohen was one of the five main students of Rabbi Yochanan ben Zakkai which included Rabbi Eliezer ben Hurkenus, Rabbi Elazar ben Arach, Rabbi Yehoshua ben Chananya and Rabbi Shimon ben Netanel. His teacher praised him saying he was very righteous (a chasid). When Rabbi Yochanan asked his students to choose the best trait for a person to acquire, Rabbi Yossi replied "a good neighbor". When he once again requested them to list the worst trait that a person should most distance himself from, Rabbi Yossi replied "an evil neighbor".