From the onset of the story "The Possibility of Evil," it is clear that something is wrong in the town. Even though Miss Strangeworth lives on Pleasant Street and the day the story opens is beautiful and sunny, the characters in this tale appear worried and upset by something. As Miss Strangeworth makes her rounds around town, she notices that Mr. Lewis looks "worried" and that Mrs. Harper's "hand shook." In fact, many people have been "disturbed lately."

As the story progresses, the reader becomes aware that Miss Strangeworth has been writing anonymous letters stirring up the evil, darker side of human nature. Strangeworth believes that "people everywhere were lustful, evil, and degraded." Through her accusatory evil letters, she has turned the people of the town against each other. However, ironically, at the end of the story, the tables are turned. She receives a letter informing her about the destruction of her precious roses. Her belief in the wicked nature of people has been confirmed.

To find examples of Miss Strangeworth being evil, look towards the end of the story when she is composing her next round of poison pen letters. Miss Strangeworth shows her darker side, for instance, by writing a letter to Mrs Crane which refers to their "idiot baby." Similarly, she also composes a letter to Mrs Harper in which she hints that Mr Harper is having an affair:

 "Is the wife really always the last one to know?"

These two examples are particularly evil because earlier in the story, Miss Strangeworth meets Mrs Crane and Mrs Harper in town and acts friendly and sympathetic towards them.

Finally, Miss Strangeworth composes another letter, this time to Mrs Foster who is due to have an operation. In the letter, Strangeworth suggests that doctors routinely make mistakes and that her nephew might encourage the doctor to do so: 

"Would Dr. Burns get his fee and a little extra from that nephew of yours?"