A Good Heart
Rabban Yochanan taught that a good heart includes every other good trait.
Rabban Yochanan once sent his five great talmidim out to find the good path a person should cling to. Rebbi Eliezer said a good eye, generosity. Rebbi Yehoshua said a good friend. Rebbi Yosei said a good neighbor. Rebbi Shimon said seeing the outcome of one's actions. Rebbi Elazar ben Arach said a good heart. Rabban Yochanan chose Rebbi Elazar's answer, because all the others are included in it. When he asked for the evil path to avoid, the answers were the opposites, and again he chose an evil heart. A good eye, a loyal friendship and careful foresight are all branches of one root. If the heart is good, toward Hashem and toward people, the rest will follow.
Source: Pirkei Avos 2:9; see also Avos d'Rebbi Nosson 14
Pick one person you find difficult and, for one week, work on your heart toward them rather than on your behavior alone. Each morning, think of one good quality they have and wish them well in your own words. You may find that kinder words and greater patience follow on their own. That is the power of the good heart Rabban Yochanan chose above everything else.