That short statement will melt away almost anyone’s anger and resentment, and replace it with emotions of calmness and attentiveness.
People are the way they are mostly due to a combination of their genetics and their upbringing, two things they have very little control over. Those who come to you irritated, irrational, and unreasonable should not be met with annoyance and hate; instead, show them pity and sympathy.
Realize that a lot of the people you meet are actually desperate for sympathy, and if you give it to them, they will be more than willing to help you with anything you need.
Say, “I don’t blame you one iota for feeling as you do.”
Continue with, “If I were you, I’d undoubtedly feel just as you do.” Say this anytime you’re stuck in a conversation where the other person is trying to start an argument with you, or is generally just in a bad mood.