Why do some sensations rub us up the wrong way, make our skin creep and crawl, or make our teeth stand on edge? The sound of chalk on blackboard is a well-known one.

Skin-creeping sensations come in two flavours: oral and aural. Some nasty oral skin creeps are: the feeling of sand in your mouth (particularly on your teeth), getting a mouthful of tea leaves in the last mouthful of tea, and nibbling emery boards (try it!). Some repellent aural skin creeps are: magic markers on white boards, opening polystyrene boxes, and garden brooms on concrete paths. And the weird thing is we all have our own...

We're Human

Of all the things that gross us out, the majority stem from things we do to ourselves or each other.

• Needles - Getting poked by needles, watching other people getting poked by needles, or hearing people talk about getting poked by needles. Why can't they just give us all pills for whatever the problem is?

• Hairy plugholes - Cleaning the bathtub, only to find 25 years' worth of accumulated bodily debris in a two-foot length of matted gunk. What do you do with it when you've accidentally pulled it out? You can't put it back down the plughole, it just won't go.

• Warm toilet seats - When forced to use a public toilet and you sit down to find that the toilet seat is warm: unpleasant or what?

• Tissues - Where your mum told you to lick it so that she could clean your face. And then all of your spittle dried up and made you feel like you had a dehydrated tongue.

• Nose and ear hairs - Need we say more?

• Warts - Big ones with huge tufts of hair in them.

• People who delight in popping and cracking joints - That awful noise of a cracking neck, an elbow, the popping of a dancer's hip socket, the cracking of fingers just asking for early arthritis.

• Putting on your dressing gown after a shower without having first towel dried, and your clammy skin sticks to the cloth.

• Pruny fingers and paper - After a long bath, and your fingers are all wrinkly, touching paper or chalk is one of the more unpleasant sensations the world has to offer.

They're Not Human

Gentle giants of the sea, all creatures great and small... nope, we won't have any of it. We can't stand dogs staring at us for long periods of time for no reason whatsoever. Or when mice make that scratching noise under the floorboards on a quiet night. Even the animals you actually want in your house can cause a major creep-fest. Our companion animals often leave us presents in the form of half-eaten sardines, decapitated mice, and the like. Some say they do this out of love for us, some say that cats in particular do this because they think we are too weak and/or stupid to find our own food. Either way, the proper response to this behaviour is said to be to consume the present gratefully. But we think running and screaming is acceptable behaviour, too.

And those are just our fellow mammals. We still have to contend with fish, which are slimy and eerie, with staring eyes, and are just all-around nasty creatures. As for jellyfish, why are they so disgustingly gelatinous? Are they really of this Earth? They're nothing, though, compared to the insect world, out there, ready and willing to make our spines tingle with their ineffable... insectness.

• Wasps and bees - Those stinging monsters that ruin any chance you will ever have at enjoying a calm sunbathing session. Our advice is to hide, leaving them until someone braver can get rid of them.

• Flies in your lemonade... to swallow or spit in polite company?

• Maggots - Has anybody ever discovered an item of food that is well past its use-by date¹ that has been populated by maggots? Or even worse, finding a dead animal and then noticing that it seems to be moving, and on closer inspection...

• Flying spiders - They are not flying spiders by the way - they are 'Crane Flies'. However, they appear to be spiders, and they appear to fly. The stuff of nightmares.

• Slugs and snails - Slimy and often found underfoot, apparently salting them is even worse than stepping on them.

• Cockroaches - Huge, brown, greasy-looking things that wave their feelers at you in a malicious way. Having a cockroach enter one's ear is a common experience in some areas. Suggested methods of removal include warm oil, cold water and local anaesthetic. Sleep well tonight!

• The whole microscopic world - Scientists insist that some of those little mites and teeny weeny bugs are required because they serve useful purposes. There's even bacteria in our stomachs which allegedly help in the digestion process. Ewww!

We're Eating

Many of us are irked by crimes against something we all know and love: food. The insertion of fancy, floppy, or ever so slightly furry varieties of lettuce into a salad, when the crunch of crisp cheap iceberg lettuce does the trick. The skin of a nice cup of hot milk that suddenly assaults your upper lip, sending you hopping around and grimacing. The mystery frozen bean in a microwave bean burrito, which tastes suspiciously like little pieces of dirty chalk. You take it out of the microwave, eat a couple of bites, and WHAMO!, that cold spot catches you by surprise.

It is generally accepted that slime has a tendency to make foods unattractive. The mucous-like texture of porridge has a knack for stimulating the gag reflex. You can make it even more cringe-worthy by adding some bananas; they have that mushy yellow foamy texture with the stringy bits on the inside of them, and skin which goes black after a while. And while we're on the subject of gooey fruit, let's talk tomatoes. Slime around tomato seeds would be almost bearable, had the 'powers that be' not decreed it impossible to buy a sandwich without sliced tomato through it; no matter how carefully you order a meal to be tomato-free, some fool will still think that it looks pretty to garnish your meal with them. Nothing against tomatoes per se, some of us just don't want them coming into contact with our food. Smoked salmon is a contender for the slimiest turn-off award, but at least it doesn't conjure up the images of cold, rubbery flesh, with those feathery legs and those black, beady eyes of king sized prawns.

Really disconcerting is when good food goes bad. You know if you leave a carton of milk out of a fridge for a week or so, and then you pour it down the sink (or even worse, unexpectedly into your mouth)? The sound of this is just unmistakable - 'Kerchunk, kerchunk, splot'. While curdled milk has to be created by leaving perfectly good milk unattended for too long, some of us shell out money for something that eerily resembles it: cottage cheese. Some of us love it, some of us hate it, but most of us will agree that the practice of adding pineapple to it makes it entirely inedible.

As if foods themselves didn't send our spines shivering enough, listening to each other dine ups the shudder factor considerably. Here's a little check list for you of things that will drive us right out of the room:

• Chewing with your mouth open

• Chewing gum - Who in their right mind decided to invent something that makes everybody look and sound like a bunch of cows chewing the cud?

• Proclaiming 'Aaaahhhhh...' after each sip of a hot beverage, blowing off hot air each time.

• Soup slurping - 'f-f-f-f-fp' - This is highly irritating, particularly as it goes on for an entire meal and can be perpetrated by a whole table full of people.

• Doing an audible intake of breath with each mouthful.

• Scraping the fork against your upper incisors as you remove it from your mouth.

• Creating the slurps, slops and suckles generally brought on by eating foods like peaches.

• Burping after a meal of, say, cheese and pickled onions.

If you can work up the courage to eat again, be sure to brush your teeth afterwards. The yellow or brown teeth of one who hasn't brushed in a day or so rates high on the skin crawling meter.

We're Listening

It's not just eating and soup slurping - there's a whole world of things we'd rather not listen to.

• The sound of brushing teeth.

• Singing out of tune.

• Anything scraping against the ice in the freezer.

• Chairs being scraped across marble or stone floors.

• Forks or knives screeching across a plate.

• The sound of someone sharpening knives in the morning.

• Nails being filed. The emery board is the worst, but any kind of metal file is pretty bad.

• People rubbing wet sandy dirt with their feet.

But the all-time most grating sound is that of dentist drills. Some of our researchers are pretty sure that if Satan exists anywhere in this world, he's a dentist. What's really terrible is when they're drilling your teeth, it makes that awful squealing noise, and odd-smelling smoke comes out of your mouth. It's as though R2D2 is in there, being tortured.

Another thing we can't stand to hear is the misuse, overuse, or just plain use of some words. The word 'special', for instance, has an abundance of connotations, none of which are very appealing. People are referred to as 'special', tourists say 'your country is so special', yet the word is used to describe a 5% discount on retail products. Even worse is when obnoxious little twelve-year-olds try to make it trendy by shortening it to 'spesh'. As in: 'come and look at my new stereo, it's really spesh'.

Another oft-misunderstood word is 'bitter'. 'I am just so bitter.' Unless you've been dipped in lemon or lime juice², you shouldn't use the word this way. There are also some words we wish just didn't exist in the first place. For example, the word 'moist', in just about any context. In the same spirit, 'panties' has a teeth-grinding ring to it³. And finally, swearing without thinking. For example, to say of a cold day, 'Man, it is cold as hell outside.' Duh.

We're... Obscure

There are some catalysts for skin crawling that may not be universal, but are certainly understandable:

• Those green paper towels in school toilets.

• People touching our belly buttons.

• Girl's dolls, especially those Victorian style china ones. They look too spooky.

• Clowns and mimes, and the nervousness that they're going to pick you as their 'volunteer' for the audience

• Mirrored sunglasses.

• Going through someone else's pockets before doing the laundry. You don't know what you might find. If you are very lucky it might be money⁴, but it maybe a wet, snotty hankie with two sweets stuck to it.

• Television programs that show impromptu brain surgeries - with the patient numbed, but conscious.

• Elvis impersonators - Why are Presley clones always in his old, fat stage? Never seen a young, slim, good looking one yet!

• Sinking your teeth into a nice sheet of aluminum foil⁵, or holding your keys in your mouth.

• Biting a wooden ice lolly stick

• Damp washcloths, and the act of sucking on them

• Cotton Wool - There is a theory that this one goes back to memories of hideous visits to the dentist.

• Necrotising Fasciitis - This is a life threatening bacterial infection that literally 'eats' your flesh. Truly gruesome!