You've met people before, so chances are you know they have the capacity to behave inconsiderately. Rather than getting angry, consider curiosity instead. As social business expert Peter Kim explains, there's often a root cause of the anger you may not expect and that can lead to a better resolution.
He explains that while trolls exist to spread anger and ill will throughout the land of the internet, there is a similar type of detractor known as the turds. Their anger usually grew from a narrative that lead them from a place of love to a place of hate with the issue at hand. He cites three examples: 1) a blogger who criticises the poor practices of a company's security only to contact them privately to ask for a job to fix them, 2) an individual who didn't get hired at a company s/he loved and now, as a result, hates, and 3) a person who feels owed something but has no means of proving it. While Peter believes money is at the root of all these issues, I think it's at least equally a problem of neglect. Each of these people became turds because they were neglected. They wanted to be heard by a company and were ignored. Their anger often mimics that of a troll, but that anger grew out of reason and comes with a problem that can be solved.
You've probably encountered these people in your own life. It's easy to return their sentiments with anger. The better option may be to be a little curious and simply ask them "Why?" Peter sums up his idea very well, so I'll leave it to him: "When you set raw emotion aside and think through a situation, sometimes surprising outcomes emerge when dots start getting connected. Next time you see a heated online exchange — whether you're directly involved or not — be curious, not furious. What you discover may surprise you."
Full disclosure: This post was made on my uncle's blog.
Be curious, not furious [Dachis Group Blog]