Another negative effect caused by noise pollution is heightened irritability and sensitivity. Different sounds can have different impacts on a person; thus, one can get annoyed with the sound of water dripping from a faucet or car horns blowing, but relax to the sounds of falling rain. Natural sounds are much less irritating than artificial sounds such as traffic noise. However, natural sounds also create a sound wall effect as in the case of a waterfall or the wind blowing. In contrast, living near the motorway can lead to frustration and can seriously upset human nerves.