Not possible? Not so! The excuse so often is that “you do not know what they did to me” as to say it is justified to be unforgiving. That might feel good for a while, or at least bitter sweet, but the person harboring the unforgiveness is the one getting the punishment in form of mental anguish and even physical illness. That said, there is a more important reason. Biblically, if one is unforgiving of others, then God will not forgive their trespasses. I think everyone needs God’s forgiveness.
How so? The scriptures that advise against harboring unforegiveness (a.k.a. condemn the practice) provide the solution. When offended, “do not take into account the wrong suffered”. It does not mean you do not recognize the offense. It means do not write it down or commit it to memory. Just let it go. It does not mean you have to subject yourself to repeated offenses willingly or associate with the person. However, it is more than let it go. You need to first pray for their well being. No fun. Then you change contempt to pity and eventually to compassion. This is the three step solution over time.
What happens if you do not stop it before going on to unforgiveness. Your attitude may advance beyond unforegiveness to what is called a “root of bitterness”. God forbid. The person in that state cannot help themselves from repeating and meditating upon the problem to their own destruction. At this point they cannot get out of it. Notice it has taken root. They cannot deliver themselves and often require others to pray they get delivered from this horrible condition.
So stop it early by not taking into an account a wrong suffered. By the way, God says he will handle it for you. Vengeance is mine sayeth the Lord. I step aside and tell the Lord to be my guest and take over before it is too late.