Therefore, as the elect of God, holy and beloved, put on tender mercy, kindness, humility, meekness and longsuffering bearing with one another and forgiving one another, if anyone has a complaint against another; even as Christ forgave you, so you also must do (Colossians 3:12-13).
We particularly enjoy people who think and behave like we do. Because none of us are completely alike, even our closest friends will sometimes irritate us. When this happens, we naturally want to complain about the other person and to draw back from the relationship. We easily excuse our anger and allow resentment to fester in our spirits.
When we do this, we are creating a sore that will become infested with unforgiveness until we wake up one morning with a hardened heart (Hebrews 3:12). It is good for us to remember that God loved us while we were dead set against him. He offered his forgiveness while we were still ridiculing his existance. Even now that we belong to him, he is calling us back to communion with him while we are demeaning one of his kids.
What we owe God is far more than what anyone owes us. Let's remember that and offer that person forgiveness.