What is the most annoying sound in the world?

The human brain is a crazy thing to think about. As the ultimate multitasker, it processes a constant onslaught of sensory information without a second thought. The flip side is that the wrinkly mound of meat between your ears is intensely sensitive to said information. Take ASMR (autonomous sensory meridian response), for instance, or leave it because the sound of someone making sweet, sweet whisper-love to a microphone or massaging a head of lettuce makes some people's heads explode — figuratively speaking, of course.

Men's Health contributor Erica Sweeney described feeling "creeped out, stressed, anxious, and even angry" when listening to ASMR videos instead of experiencing the pleasant tingling typically associated with the clips. ASMR University founder Craig Richard called the disparity a scientific mystery. However, there are some working theories as to why, one of which involves misophonia, a "hatred of sound" that triggers a fight or flight reflex. But there are also some sounds that people just generally hate, sounds that make human brains boil with the fury of someone who paid top dollar to attend a rock concert, only to discover that the band consisted solely of mimes with imaginary instruments. But what's the most annoying sound?

Cuts like a knife on a bottle

Some of you will be shocked to learn that despite all the fashionable rage they've inspired over the years, Nickelback is not in fact the most annoying sound in the world. Chewing ice would also be a nice pick because it's like an ice pick to the eardrums. But according to Smithsonian, a study published in the Journal of Neuroscience in 2012 found that the undisputed champion of auditory torment is a knife on glass, which sounds remarkably like an instrument in a symphony of serial killers. But no, it's just a pain in your ear's butt. 

The researchers speculated that people feel a strong aversion to a knife scraping against a bottle because the frequency might fall within the range of an alarm call by an evolutionary relative like a chimpanzee. So it might be that your reptilian brain is aping a fellow primate.