What Do I Owe Them?
Instead of counting what others owe him, Rav Ben Tzion counted what he owed them, and found no room for resentment.
Rav Ben Tzion explained how he kept peace with everyone. Most people keep a ledger of what others owe them, and every slight is entered in it. He turned the ledger around. He went through the commandments that govern relations between people: to love a fellow Jew as oneself, not to hate a brother in one's heart, not to carry gossip, and not to take revenge. Then he asked what he owed each person on that list. He found the total so great that no room remained for a quarrel. How, he asked, could he fight with those he owed so heavily? He lived this way too. Every night before sleep he forgave all who had upset him, and when he found it hard he would sit up in bed and work at judging the person favorably until no grudge remained.
Source: Yated Ne'eman feature on Rav Ben Tzion Abba Shaul (his own saying, recorded in his name); the printed source in his seforim has not been located.
Tonight, before you sleep, think of one person who has hurt or annoyed you. Instead of listing what they owe you, list what you owe them as a fellow Jew: respect, a good word, a favorable judgment. Then say the forgiveness paragraph of the bedtime Shema slowly, and mean it. If it still feels difficult, do as Rav Ben Tzion did and sit with the thought a little longer. Waking up lighter is worth a few uncomfortable minutes.