“What I needed was an emotional Geiger counter that could objectively measure other people for sadness. I looked at the woman in the car next to me. She was applying makeup during the stops, opening and closing her mouth like a feeding fish, staring at her red lips in the rearview mirror. I imagined holding the Geiger counter to her forehead. I would ask her a question about her children. Were they an accident? What dreams did they make impossible? She would say, “They are the best thing I ever did,” and the readout would expose her lie with a pixelated frown.”