For the sake of your happiness and for the sake of everyone’s happiness, you want to be able to express thoughts of goodwill even to very difficult people.
"If you develop a mind state where you realize you have no ill will for anyone, it gives you a sense of strength and nourishment, and as the Buddha says, it provides protection for you in all directions, into the past and into the future. What this requires, though, is that when you’re developing goodwill [mettā], you don’t simply think over and over again, “May so-and-so be happy, may they be happy, may they be happy.” You also have to think, “Is there anyone out there for whom I cannot have genuine goodwill? Why can I not feel goodwill for this person?” If they’re misbehaving, genuine goodwill means that you’re wishing that they will have a change of heart: that they’ll change their ways and behave more skillfully. Now, is there anyone out there who you would like to see suffer before they change their ways? If there is, ask yourself, “Okay, why? What are you feeding on?” It’s usually a sense of revenge. And even though they say revenge is sweet, it’s miserable food. It woul...