Common side effects of zinc reported in the trials the studies reviewed included issues with bowel movements, nausea and an unpleasant taste.

While most people are blissfully ignorant of their wastewater’s journey after showering or using the toilet, it’s become an unpleasant fact of life for many El Segundo residents.

She tells the BBC the unpleasant feeling afterwards can eat away at her for hours.

Consuming addictive substances often involves an unpleasant experience, like using a needle, ingesting a bitter substance or inhaling smoke.

"Living a life continually looking over your shoulder is very unpleasant," he said.