Water Under The Bridge
From time to time an uncharitable thought or memory may arise in my mind regarding the actions of a fellow Jew. If I cannot push it out my head immediately, I ask myself, "When did this event occur? Did it just happen, or did occur before Yom Kippur?"
If it occurred before Yom Kippur, I remind myself to assume that this was an action the person did teshuva for. If I truly believe that Yom Kippur wipes away my aveiros, I must believe that it wiped away this person's aveiros as well.