If you only practice loving kindness (metta) for people you love, like or indifferent to, you wouldn’t really need the practice. Sure you can increase metta for those you are indifferent to, but then you would only be a part-time Buddha or a fair weather Buddha.
If you have seen the movie Gandhi, you may recall that as Gandhi is dying, a Hindu man approaches him who was afraid of going to hell because he killed a Muslim boy. He did this out of rage, because the man’s son was killed by a Muslim. Gandhi told him to find a Muslim orphan to raise him as his own.
We have our own private hells in our hearts that result from the three poisons: delusion, greed and ill will. Ill will feels horrible. Holding onto resentment is corrosive. Not only does it cause you suffering, it never evens up the score. So you resent that the target of your anger is never punished, which piles resentment onto resentment. It feels unfair. It affects your outlook and how you treat others. The old adage is that “Resentment is like drinking poison and waiting for the other person to die.”
Metta practice for difficult people is like raising that Muslim boy. You begin to see beyond the differences and see the fundamental humanity that unites us. They have shortcomings just like we do, but they also have hopes, fears, loves and loss.
As you begin to develop love in your heart for these people, you are in a better place to communicate with love and care. If they grow to like you, you could convince them of the error of their ways. Does this sound overly idealistic? Ever heard of Daryl Davis?
Daryl Davis is one of my all time heroes. He was an African-American man with the love and the courage to approach Klansmen. Often he is the first black man they have ever met. He would sit with one of them over beers and discuss everything with him, focusing mostly on the things that truly matter: family, friends, hopes, fears, hard times, good times. He would invite them over to his house and go to theirs. Several Klansmen have renounced racism because of his friendship and gave him their robes which he kept as a momento.
Good luck with your practice.
To learn more about Daryl Davis:
Painting: Three poisons surrounded by the positive and negative actions motivated by the poisons; detail from a bhavachakra