When you can’t tolerate someone smacking their lips while eating it’s called Misophonia. I’m wondering why they say we have the problem as the listener instead of the eater! Basically this disorder means sufferers have a hatred of sounds such as eating, chewing and breathing loud.
Researchers have done study after study, even used MRI’s to measure the brain activity of people with and without misophonia while they were listening to a range of sounds. You can find more information here.