I can love the person who is difficult to love. How can I do that? Because love doesn't depend on how I feel. Love is a decision I make, to prefer another above myself, to be like my Father Who defines love.
If I do not love when someone is rude, or critical, or churlish, then my love is conditional, and is not like His. True love shines brightest when it is hardest to love.
Love bears and forebears. Love forgives. Love breaks down the barriers that pride builds. Love changes things, changes people.
I can love others who are difficult to love because... HE loves me.