5th of Tishri, 5771
In preparation for Yom Kippur, we should examine if we had harmed anyone: a friend, a colleague or a member of our family. Yom Kippur and Viduy (confession) are good to atone for those transgressions between us and God. (Shabbat, Kashrut, Tefilin, etc). But on Yom Kippur we are not forgiven for the offenses made toward another human being, unless we ask first for their forgiveness. Therefore, the most important preparation for Yom Kippur is to reflect in our minds whom we might have harmed and ask for his or her forgiveness.
To ask for forgiveness is probably one of the most challenging tasks we might need to do in our lives. Because we need to admit (and say): "I WAS WRONG".
What happens if the victim does not want to forgive us? "He should take along three men to intercede for him and plead with the offended to forgive him. If necessary, he must repeat and try three times as his penitence. ... If he asks forgiveness three times and the other refuses to forgive, he need not return again..." (Meam Loez)
However, if one offended his father or mother, there is no limit to the times he needs to go and ask for their forgiveness.
In the same way we expect other people (and God!) to forgive us, we need to be easy to forgive and forget. "Before going to sleep at night we should say: if anyone has injured or offended me in any way, I forgive him completely and I bear no hatred toward him. One thus fulfills the commandment 'You shall love your neighbor as yourself'