I have a close friend who described to me, at length, the annoying habits of the person who sits closest to him at work. He went on in such detail that I felt like I was there...
The first and most notable annoying habit is the "violent nasal exhalation". Basically, we all have an opening that connects our nasal cavity to our mouth. Apparently, the annoying guy closes that off, builds up pressure in his mouth, then opens the nasal passage. The result is similar to the sound he would make if he was blowing his nose, but immediately preceded by a kind of "thunk" from the explosive opening of the mouth-to-nose cavity.
I've never heard a whale expel air through its blowhole, but I can only imagine it's very similar to what this guy does.
Of course, such a habit could easily be ignored if it occurred infrequently. My friend---who is never prone to exaggeration---says the guy makes the noise at least once every minute. Every minute!
The guy's next habit is less frequent, but louder and much more prominent: the "mouth vacuum". This involves opening the corner of his mouth and forcefully sucking in air. I've heard people (and probably done it myself) do this when their mouth is full of saliva. Of course, the silent alternative is just to close your mouth and swallow.
That he does it out of the corner of his mouth is important: the side he does this with is the same side on which my friend sits. It's as though the sound is directed squarely at him. It's quite loud too: loud enough that it can be heard in the whole office. But of course, my friend is at ground zero, where it's loudest and impossible to ignore. Frequency is lower than the nose thing, but still at least every five minutes.
Hacking and spitting. One to four times an hour, he'll hack up what ever drainage or phlegm he has in his sinuses, and spit it into his garbage can. As an added bonus, sometimes he'll skip the garbage can and use the sink in the office's kitchenette. My friend said that the other day, he heard the annoying guy hack and spit into the sink. That in and of itself was unremarkable, nothing new. But then my friend went over to the sink to rinse out a mug... and there it was, in all its phlegmy glory: a giant, yellowish ball of mucous, sitting innocently in the sink, half-way between the drain and the edge. He hadn't even bothered to rinse it down the drain! A public office sink turned spittoon.
He occasionally gets into throat-clearing fits, which becomes the culmination of all his foul habits. He'll sit there and continuously clear his throat for a solid minute or two, punctuating his clearings with violent nasal exhalations. Often a mouth vacuum or two is thrown in for good measure, and the spectacle's grand finale is hacking a big loogie into his garbage can. Fortunately, this only happens, on average, a couple times per day.
On days when my friend is really lucky (sarcasm), the guy will accompany every violent nasal exhalation with a throat-clearing. Like a lone barking dog, the sounds are too frequent to ignore, but not frequent enough to fade into the background.
My friend's office is small and generally quiet---whisper quiet, in fact, with an open seating plan (i.e. no cubes or anything dividing up one person's workspace from the next). This means that even the slightest of sounds can be heard.
The annoying guy uses this library-like silence to achieve his full annoyance potential: lip-smacking. Generally, such behavior is reserved for animals and sloppy-eating cartoon characters. But during, and for several minutes following any eating, the annoying guy manages to continuously slurp and smack his lips. If he only ate once or twice a day, perhaps these noises could be ignored. But most days, he eats at least six times: breakfast, lunch, two to four yogurt snacks, two to four nut snacks. And then there's the cookies: between all the other meals and snacks, he'll toss a whole cookie in his mouth, and just suck on it, presumably until it disintegrates. The sucking is of course open-mouthed, and practically at broadcast volume for my friend.
Also rising above the silence are random whisperings are finger snaps. Throughout the day, the annoying guy randomly whispers and snickers to himself. My friend doesn't know what causes the guy to talk to himself; presumably, he's thinking through something. But the giggling comes about when he's reading online forums and/or email. Once, the guy was so moved to laughter, that in an attempt to muffle the outburst, he actually produced the most awkward, hyena-like noise my friend has ever heard a human make. And if the random whisperings weren't distracting enough, they are often peppered by finger snaps. Yes, the guy snaps his fingers off and on throughout the day. It's not a constant snapping, just two or three snaps---as though he is trying to get someone's attention.
The solution to my friend's problems? McMaster-Carr part number 6207T53: taper end foam earplugs with a noise reduction rating (NRR) of 33 dB.