You're mid-sentence explaining why your printer won't connect to WiFi when your friend's eyes go into full node-mode—head bobbing like one of those dashboard dogs. You push through anyway: "So the router's on the 5GHz band and the printer only supports 2.4, which is why—" Their head nods faster. You pause. They nod through the silence. You just watch them until they realize they've been nodding at nothing for three full seconds, and they panic-nod one more time as if that'll make up for it.