6. Hiccups were inherited by people from their ancient ancestors.
Hiccups are a leftover of our distant ancestors who lived 370 million years ago. These guys used to swim in the ocean, therefore, their bodies were provided with gills and lungs at the same time (there are still fish in Australia that can breathe using this method). With the help of the mechanism that we call hiccups, our ancestors used to protect their lungs from water ingress.