This is the tendency of some characters to forgive other characters no matter how serious the wrong. This includes those other characters Jumping Off the Slippery Slope, murdering loved ones, or raping the person granting the forgiveness. In extreme cases, a character granting Insane Forgiveness will grant it to someone who already crossed the Moral Event Horizon. It's the principle of "forgive and forget" taken to extremes. Most viewers will be left scratching their head, wondering, "How can they just let that go?" Sometimes, other characters In-Universe also have this reaction.