Throughout Yom Kippur we recite the many confessions found in our mahzor-liturgy, even though they may not apply to us specifically. Why? These confessions are phrased in the plural because the Jewish people are responsible for each other. If someone else has done something wrong, then on some level I am responsible. Another reason is that sometimes we don’t remember what we’ve done or we’re not fully aware of our own actions. Reciting all manner of confessions triggers our memory and helps us with the soul-searching that Yom Kippur is about.