We've all been in the company of that person who constantly cracks their knuckles, grinds their teeth or picks up and fiddles with everything in sight.
To us, these can be frustrating traits. To them, these are habits they just can't seem to break.
But most of us -- and the people we annoy -- don't know why we do these things. Are we bored? Maybe we're nervous? Or maybe the action is so ingrained into our everyday we don't even know we're doing it.
It turns out there's an explanation behind why we take to our nails, hair, knuckles (or all three) while we're feeling on edge.
According to clinical and coaching psychologist and Chief Happiness Officer at The Happiness Institute Dr Tim Sharp, otherwise known as Dr Happy, our everyday habits have been designed as a way to reduce discomfort.
"Habits are not always developed by the same cause or for the same reason for every person. However, they do tend to be behaviours that provide some sort of comfort to something that was or is initially stressful or distressing," Sharp told HuffPost Australia.
"The generally common theme among all habits like nail biting or hair twirling is in some way or another, in early stages, something associated with those behaviours caused some degree of discomfort, and the action relieved that anxiety and provided comfort."
So how do these momentary stress-relieving actions develop into everyday, repeated, routine behaviours that drive our friends and family members mad?
According to Sharp, although there may be an initial trigger, habits, by definition, become automatic or unconscious over time.
"After a while, the original cause may not be there any longer but the habit just continues unconsciously and a lot of people aren't actually aware of it –- if you interrupt a nail biter while they're biting their nails they often won't even realise they're doing it."
How a lot of people actually get treatment for habits [is] because their friends, partner, husband or wife actually force them to get it sorted because it's annoying for them too.
While our most common everyday habits include things like fidgeting, biting our nails, twirling our hair and grinding our teeth, what you may not know is our strange superstitions such as triple checking the oven is turned off, or our obsessions with keeping the TV volume on an even number, are still considered habits.
Sharp describes these kinds of tendencies as 'a lack of ability to tolerate uncertainty or to tolerate some degree of imperfection'.
"When someone has these more extreme habits, they can occur because of what we call wishful thinking or superstition -- for example checking locks. The checking is the compulsion, but the obsession, wishful thinking or superstition is the thought that if we don't check the lock, the house will be robbed or someone will be harmed," Sharp said.
It's once a habit like this starts to interfere with everyday life, that it may overlap with the obsessive compulsive category.
"Another common one is hand washing, the compulsion is washing your hands, the obsession is the thought that if my hands are dirty, I'll catch an illness or spread an illness -- it becomes extreme habitual behaviour when people do this to the point of rubbing their hands raw or avoiding touching things."
According to Sharp, while habits that disrupt your life are most likely to disrupt the lives of others too, this might actually be a good thing.
"Checking the locks five times before leaving the house could make me late to things, or constantly changing the volume when other people are trying to watch TV, that's irritating for them too. Cracking knuckles makes a noise that some people don't like, that's frustrating for other people.
"But, this is often how a lot of people actually get treatment for habits because their friends, partner, husband or wife actually force them to get it sorted because it's annoying for them too," Sharp said.
Interestingly, according to Chris Golis, who is a Practical Emotional Intelligence Expert, whether or not we keep an eye on the clock is also habitual behaviour.
Golis explains that being late on repeated occasions isn't really because your car broke down again or you lost your house keys for the fifth time this week, it's because forgetting to arrive on time is actually a habit. Looks like it's time to forget all of our excuses!
"With the people who are always late, there is always an excuse -- my bus was late, I couldn't find the place, the lift was stuck," Golis said.
"But there are two types people who are late -- one group who are always distracted on the way, but as soon as they arrive, they immediately apologise, tell a funny story and immediately use your first name.
"The other people who keep you waiting are the 'politicians', because they want you to know who's more important. They don't apologise, and the first thing they start doing is try to work out your status," Golis said.
If you're finding yourself tapping your feet, jiggling your knees up and down underneath your work desk or reaching for your fidget spinner, (which Sharpe explains is actually an interesting way to recognise your habit by turning it into a fun game), stop and recognise the situation -- there may be another way to relieve your discomfort that doesn't involve a loud, bone cracking pop in your work colleague's ear.
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