Atticus Finch, of Harper Lee's masterpiece To Kill a Mockingbird, treats all people the same way.
Atticus is a man who is led by a moral compass that never fails him under any circumstance. Scout reports that she has never heard him raise his voice. Whether he approves of another person's actions or not, Atticus remains constant: quiet and respectful.
With his friends, like Miss Maudie, Atticus is cordial and good-humored. For people like Miss Stephanie and Mrs. Dubose, he goes out of his way to be positive and/or complimentary. Atticus gives advice to Jem, specifically, on how he should act with Mrs. Dubose.
"Easy does it son, son...She's an old lady and she's ill. You just hold your head high and be a gentleman. Whatever she says to you, it's your job not to let her make you mad.
And in meeting the cantankerous woman himself,
Atticus would sweep off his hat, wave gallantly to her and say, 'Good evening, Mrs. Dubose! You look like a picture this evening.'
When the men from Atticus' community come to speak with him about defending Tom Robinson, Atticus listens quietly and responds the same way. When the mob comes to the jail to lynch Tom Robinson, Atticus is calm and gracious in addressing the men before him. He becomes fearful when the children arrive, instructing them to leave, but he does not raise his voice even when they refuse to do so. (Scout ultimately diffuses the tension—and the group—as quietly as Atticus might have.)
Perhaps the clearest example of Atticus' ability to rise above the behavior of others without losing his temper is the way he acts when Bob Ewell spits in his face and threatens to kill him. Atticus' only response later is:
I wish Bob Ewell wouldn't chew tobacco.
And later, that was Atticus' only comment about the incident. However...
Miss Stephanie said Atticus didn't bat an eye, just took out his handkerchief and wiped his face and stood there and let Mr. Ewell call him names wild horses could not bring her to repeat
and then [he]...
put his hands in his pockets and strolled on. Miss Stephanie said you had to haind it to Atticus Finch, he could be right dry sometimes.
Atticus' only weapons are his integrity; his belief that to understand others you must walk in their skin; and, to "kill others with kindness" regardless of their behavior.