It is been my experience that I am rarely able to "fix" the behavior of challenging people in my life. Responding with emotion to difficult people never produces long-lasting change. I believe that perhaps God has placed you in that difficult person's life not to moderate their irregular behavior, but to pray for them. It is a simple equation that God gives us to deal with those irritable and troublesome hunks of humanity: Love + Prayer = Victory.
God's strategy rarely involves emotion but always has liberal doses of love and prayer mixed together for a victorious conclusion. God did not create you to be some whirling dervish who uses words to jab, hurt and control people. God created you to be a man or a woman who was more committed to Kingdom than to self. Difficult people can run away from your words, but they can never escape your prayers. We cannot and must not have a disconnect between what we believe and how we treat others, no matter how difficult they may be.
There is an anecdote for bitterness and wrath; it's called kindness. There is a way to overcome anger and clamor; it's known as being tenderhearted. There is also a way to conquer slander; it's recognized as forgiveness.
It takes a mature, Godly Christian to bless the persecutors in life. We bless with our tongues, with our heart attitudes, with our emotions, and with our actions. Some of you might be thinking, "Yeah, but you don't know my Aunt.....! She is unlovable in every way imaginable!" You may not want to hear my response to your Aunt scenario but here it is, Somebody loves your Aunt and His name is God, so start acting like your Dad!
We are all unlovable in some way, aren't we? We all can become prickly, outspoken and contentious from time to time, but I believe that the reason most of us are unlovable is that at our very core we are crying out to be loved. There will be many times in life when your decision to love a porcupine will disarm them completely.
If you refuse to forgive and then bless the difficult people in your life, you are in danger of becoming a difficult person. The equation is no-fail and will guarantee your eventual victory: