The pastor of my church in Augusta, the Rev. Erik Karas, recently told this story: “A very smart man once told me, ‘One day someone in church will come to you and rant and rail about the cake at coffee hour. Remember, when that happens, it’s not about the cake.’” By that, he meant that the cake curmudgeon wasn’t purely upset about the dessert, but that the cake is a symbol of something bigger bothering him.

Not surprisingly, Rev. Karas shared this wisdom in the context of the uproar over the United Airlines “reaccommodation” of a passenger in Chicago. By now, you have probably know about the doctor who was forcefully removed from a flight he had already boarded.

This — and the example of the cake — are good examples of what political scientists call a “condensation symbol.” The concept was developed by Doris Graber in the mid-1970s, and it is still useful today. Sometimes even a relatively small event — words can do it, too — absorbs lots of meaning because it reflects something bigger.

In the United case, a lot of things came together to do that. It released long-simmering frustrations with corporate doublespeak, feelings of loss of control in modern society, lack of civility, feeling treated like a number by big businesses, questionable public relations work, and the difficulties of travel. Some people have even turned the majority view on its head and argued the case is about rude passengers.

In this case, one person being taken off a plane — albeit violently — took on a bigger meaning than it normally would because the facts of the case trigger these feelings. Such is how condensation symbols often are born: One thing comes to stand for a lot of other things.

And when that happens, people want to talk about it! Condensation symbols can be therapeutic for people to discuss, and they help make sense of the world for us.

The memes and jokes and discussion of the United event give people the chance to say, “There! That puts the finger on something I’ve been thinking for a long time.” But it’s important to be careful with something that feels like a good symbol of what we’re thinking and allow new facts to change our mind as they come in.

Once established, it is hard to shake a condensation symbol from people’s minds. And, it’s important more than ever that we grasp condensation symbols and what they mean from the start. In a world of social media and video shot on mobile devices, word spreads faster than ever about the very kinds of incidents that can become condensation symbols faster than overnight.

Sooner or later, new condensation symbols will emerge.They sure keep condensing like fog over United. In the same week, a scorpion was found on a United plane and there was the revelation of an incident where a first-class United passenger was told he had to give up the seat he paid for to a late arriving “higher priority” passenger or he would be handcuffed. This combination creates a new condensation symbol of United as a home of unfriendly skies. But as big as the PR problems United is facing are, many of us are expressing frustrations far bigger than any one airline, or one piece of cake.

Jim Melcher is a political scientist at the University of Maine in Farmington.