1. Vomiting
Does the sound of vomiting make you feel queasy? In a study of 385,000 internet responses to 34 unpleasant sounds, vomiting was rated as the worst. The sound of vomiting is so nauseating because of your mental associations to it. It brings up people’s most repulsive feelings of bodily discharge — in all its unhygienic glory. Interestingly, the acoustic properties of vomiting are not particularly noxious: it is neither rough nor sharp. Sensations associated with disgust are especially well learned by mammals because this skill is necessary to avoid poisonous foods.