Public toilets

Why are sensor-operated hand-dryers impossible to use? Either you put your hands in the path of the sensor to activate it, OR you put your hands in the warm air. There is no way to activate the sensor and enjoy the hand-drying benefits of the stream of hot air at the same time. As a result, you end up flapping about with wet hands, before taking the inevitable decision to wipe your hands on the back of your trouser legs. Grrr.