That brings us to our second ingredient in the recipe for what’s annoying. Whatever it is—a buzzing mosquito, a pestering child, a dripping faucet, or half of a cell phone conversation—it has to be unpleasant. Not horrible, not deadly, just mildly discomfiting. Whether halfalogues are distracting because they’re rude or rude because they’re distracting, it’s rare to listen to someone else’s cell phone conversation and enjoy it. Some things are inherently unpleasant—the sound of fingernails on a chalkboard probably falls in this category—and others are more unique to the individual. Some people find being stuck in traffic unpleasant; others don’t seem to mind a bit.

Overheard cell phone conversations point to a third and final ingredient in the perfect recipe for annoyance: the certainty that it will end, but the uncertainty of when. To be annoyed requires some impatience on your part. The conversation could be finished in a few more seconds, or maybe it will stretch on for another hour—it’s the knowledge that the unpleasantness will come to an end soon that gives a particular situation an edge, a sense of urgency. That is, your annoyance is related to your sense of optimism. Your hope that it will be over amplifies every additional second that you have to put up with it.

Annoyance is probably the most widely experienced and least studied of all human emotions. How do we know that? We don’t really. There is no Department of Annoying Studies or annoyingologists. There are no data, no measurements of how many people are annoyed or how annoyed people are, no investigations into what makes people annoyed, and no systematic looks at how people cope with annoyance. In fact, if you talk to psychologists, practitioners of a scientific discipline that one would think would have grappled with annoyance, you get the feeling that there might not be such a thing as annoyance at all.