Every person reading this has been hurt by another. Sometimes it has been inadvertently, the other person never even aware of the transgression. Sometimes it has been intentional and malicious, the other person trying to injure with their words and actions. How we deal with these issues says far more about ourselves than the person who has wronged us. Forgiveness sets us free. It makes the other person's words and actions meaningless. It takes away the power that we are allowing them to continue to hold over us. Forgiveness even benefits us physically. Being bitter can actually affect our cardiovascular and nervous system.
Others have said it much more eloquently than I could ever hope to:
For if you forgive other people when they sin against you, your heavenly Father will also forgive you. ~Matthew 6:14