When I show grace and forgiveness when I am wronged, I am not responding to that person.  J. D. Greear says, "Ultimately, I am responding to Jesus, not to the person in front of me. The person wronging me may not deserve a response of grace, but the Jesus who bled and died for me does."
And expecting them to change is often unrealistic. Think about the time you first heard the gospel...was there an immediate response? Jesus extended His grace to me long before I changed.

"Even if showing grace never changes those we forgive, it changes us, and that is God's primary purpose in all that is happening to us in this life." For the sake of His overwhelming grace and mercy on me, for the sake of those around me, and for the sake of my own personal sanctification, may I be approach today with the spirit of one who has been "forgiven much" so that I may love like God does.