If you have never driven a car before, it is a bad idea to enter a car, turn on the ignition and drive into a road filled with speeding vehicles. The terrifying experience might see you wake up in the intensive care unit of a hospital.
If you have never made a public speech before and step forward to deliver a speech, you may stutter, stumble and not make too much sense. The experience feels as terrifying as rolling untrained into a highway. But after a few minutes, nothing disastrous happens.
Our mind mistakes certain benign events to be deadly encounters. Manually overriding this tendency can help you put your hand up and step forward even as the people around you are paralyzed by fear.