Using technology to convey information and feelings between people is a key goal of many interactive systems, typically with the highest connection fidelity possible. However, the choices made during design and implementation inevitably impact how the communication is perceived. As part of the Empathy Mirror project , we explore using technology to instead invert the expressed physical aggression of one participant into a soothing massage for another. Participants take out their aggression on a punching bag. The system detects the magnitude of the blows, and processes them into vibrations rendered via a massage seat to a second participant. Participants reflect on how technology can subvert our intentions, such that the receiver’s perception may be very different from what the sender originally communicated. In this case, the most aggressive action is to remove themselves from the exhibit, leaving the receiver with no positive vibes, effectively nullifying the ability to be hostile.