Greet others before they greet you. The Talmud teaches that Rabbi Yochanan Ben Zakkai made it a virtue to greet others in the marketplace before they greet him, even gentiles. You may want to crack a smile or roll your eyes that thousands of years ago, it was noteworthy that someone would honor people from outside his own community. Yet even today, when racism, tribalism, and unconscious bias are significant drivers of human behavior, someone who is blind to color and class is remarkable and praiseworthy; how much more so two thousand years ago!
In accordance with this tradition, try to greet everyone before they greet you. A greeting may be a smile or it may also include a heartfelt hello. Be sure to greet people who are both different and less fortunate than you are. Try this for three days in a row, and record your experiences in your journal. How did it feel at the end of the day compared with the beginning of the day?
— Greg Marcus in The Spiritual Practice of Good Actions