Most of the ideas that already exist in the world, I would actively reject out of fear, examples, putting current carrying wires into water (heater), metals wei

Most of the ideas that already exist in the world, I would actively reject out of fear, examples, putting current carrying wires into water (heater), metals weighing 800 kg moving with high speed (cars). So I guess we (at least I) are rejecting quite a lot of potentially useful ideas?