Aperture

A therapist receives a cryptic message in his handwriting: "They understood perfectly." While trying to figure out who wrote this, he learns that all his patients are using the same therapeutic language to justify their cruel behavior toward others: validation, boundaries, emotional honesty.
He starts to investigate his patients' links and eventually sees a connection that indicates a mastermind manipulator at work. However, as he digs further into each case, he realizes that there is no mastermind manipulator as he initially feared.
The "manipulator" is simply a normal, unremarkable person, just someone telling people what they want to hear, giving them permission to give in to instincts they already possess. And worst of all, the therapist is doing the same things with his own patients, instructing them on how to rationalize their own worst behaviors.
The story is also about how human cruelty does not have to be complex; it can be satisfied with validation. It touches on the idea of complicity, intentions versus consequences, and the ease with which people can justify cruelty to another person, given they have been told they are right to feel as they feel.