logical

This is essentially incorrect; the vast majority of people here use the inferior system in everyday usage.

But there are everyday examples where both are used.
E.g. If you see someone drinking a soda and ask them how much sugar is in it they'd probably tell you a number in grams.
Or if you have to take cough syrup the dosage is usually in milliliters.
Or if you ask someone what size engine their car has they'll most likely tell you in liters.
- And no one brings up that the UK actually uses both and in a lot more confusing way. Fuel in Liters but efficiency in miles per gallon. Speed in miles per hour but how far you drive in Kilometers. Weight of produce in grams and people in stone.
  
  And even then British gallons are different from American gallons so the efficiency numbers look really frickin' weird.
  
  This isn't very accurate. Imperial is used for car and travel related measurements, metric is used elsewhere (officially). It would be nice if we switched to metric but it is OK.
  Fuel in Liters but efficiency in miles per gallon.
  Yeah, I think this is basically the only confusing and annoying imperial/metric thing we have.
  Speed in miles per hour but how far you drive in Kilometers.
  We don't use kilometers for how far we drive. We still use miles on signage and in everyday speech, along with miles per hour. I imagine if we switched to kilometers per hour, we would start using kilometers.
  Weight of produce in grams and people in stone.
  Older generations might still use stone but it is disappearing. Even my retired dad uses kg now. Younger generations are not taught stone (for decades now), as they grow up it will disappear.
  It is a similar story to height in feet and inches. It is becoming less common, but probably slower than the switch away from stone.
Plus, many of us are in STEM fields and appreciate/prefer the metric/SI system. However, we think in imperial units because that’s what we used in daily life in our formative years.
I have no problem with metric units, but I do a rough mental conversion to imperial to relate to the measurement, and get a “feel” for it. This goes for temperature, distance, speed, volume, weight/mass, pressure, and essentially anything else that’s an everyday unit.
It’s analogous to how much of the world thinks of nuclear explosions in terms of kilotons or megatons of TNT. I mean, all you have to do is multiply megatons by 4.184e+15 and you’re back to the sensible unit of Joules. :)
- I go back to what my professor in my first engineering class told us -- a good engineer can work in any unit system.
  At the end of the day, imperial vs metric is an argument you have over some beers with friends. It's inconsequential.
  
  That's a damn good point, the distance doesn't change regardless of what you call it.
  
  Exactly. This isn't rocket science, it's simple math. And by knowing two unit systems, you can describe the distance in the most convenient way possible.
  
  Hell, I'm not an engineer and that's something I was taught in school. In Texas. In the 80's.
  Man, this place has devolved so horrendously...
  
  Man :/

You are funny. Most places do not use "both". They use metric and... Sometimes they switch to metric for good measure (hah!). To believe that the whole world does the old convert around is confirming another US stereotype (everyone else is like we are and that's a given) while you try to get us to stop mocking us stereotypes. Oh the irony!

It's true that the vast majority of the world uses only metric but Western English speaking countries tend to use a mix.
The UK is mixed, Ireland (where I am) is mostly metric but a person's height is still mostly imperial and butter is sold in 454g packs (a pound) and older folks still measure their weight in stones and pounds, Canada uses a mix (my sister lives there and we discussed this recently) and the US uses metric where appropriate (science, military, medicine).
Are you saying that only the US really constantly has to do conversions between both systems? Are you saying that Americans are always doing a bunch of math that the rest of you aren't?
- I regret to inform you that... Yes, you are doing some math other's don't. Except for the British, those people are beyond savior with their obnoxious mix of weird unit collections.
- Yes, only places where it is mixed is the anglosaxony... try to open to the world.
  I use pounds because I do archery, where my bow's power is measured with that unit, which I translate as 1/2 a kg. I don't care that it's inaccurate.
  There are also inches (I think) for Tv and computer screens, which is shitty.
  But no one else uses imperial.
  I worked with croncrete blocks (prefabricated building elements) some years ago and I was all the time making fast calculations of sizes and weight and I cannot imagine making that in imperial (admittedly because I am not used, but in present case it would just have been massively impractical)
The only irony here is your ignorant self mocking me for my alleged ignorance. Most countries don't use metric and imperial, but they use metric and something.
And just as general advice, mocking and generalizing other people due to their nationality is a primitive and smoothbrained behavior. Grow up.
- Ah... No mate, there are no "somethings" for "most countries". Most of the world uses straight up metric and that's it. What "local systems" do you know of that get used alongside metric?
  And regarding the grow up part... See, here in Europe everybody will crack jokes about everybody else. French laugh at Germans, Polish mock the Spanish and everyone laughs at the British because they can't come back at us since they had their little voting oopsie and now need a form to import jokes into the EU.
  Remember that one kid that never got the joke, took what was said in jest at face value, got upset and thus mocked even more? Americans have a surprising tendency to be that kid.
  
  There are "something" for a lot of things that are not in metrics.
  Like tire sizes. My bow's power is measured in pounds (and I should use inches there too normally. I don't bother.) Screen sizes are in inches I think...
  95% work in metrics. But there is always a little stuff in some weird units.
  
  "Remember that one kid that never got the joke, took what was said in jest at face value, got upset and thus mocked even more?"
  Please stop, the irony, it's too much.

You don't use both, or at least, surely you mean "both" for cases where you are forced, like me by American online stores. And this joke won't stop until you get rid of that shitty system.

Except we do use both. Sorry but you're just wrong.
And sure, you're entirely welcome to keep making the same joke over and over and pretending it's still funny. Show that dead horse who's boss.

I mean, not really.

Your maps, road signs, and speed are still in miles, height is still in feet and inches, weight is still in pounds, etc.

In Canada, we may use imperial for a few colloquial things, but everything for official use is in metric.

Ok, for one, that's...still using both.
Two, I only wish we measured codeine in pints.
Three, and this is genuine interest/curiosity more than an internet gotcha — either you're downplaying it because Canadians are really weird about making their whole identity The Country That Isn't The US, or the Wikipedia entry on this is incorrect and should be fixed.
I'd always heard the roadsigns in Canada were primarily metric but could be in both, whatever, could be regional, willing to disbelieve hearsay. But I don't think that cooking in tbsp, cups, and fahrenheit, or selling food by the pound and draft by the pint are really small colloquial concessions. Not to mention with the tool measurements, which we admittedly kinda force.
It's to varying degrees, but all the same, we both use both. US milk is in gallons, but all soda shall be in liters. If we wanna get technical about which measurements are the ones professionally used, both countries go metric.
What I found the most amusing: the healthcare section notes that Canadian measurements in the medical field may be different from American ones despite both of those being in metric, presumably just to be contrary

Very few countries use both systems.

True but the ones that do are Western English speaking countries like the UK, Ireland (where I am and which is in the final throws of ditching Imperial), Canada and to a lesser extent the US, which uses metric where appropriate.
Those countries are going to be disproportionately represented on here.
I read an article many years ago on why the the US hadn't gone metric and cost is a huge factor. Just replacing all the speed signs across such a huge land mass would be serious money for example with limited benefit.
Folks deal with the change itself just fine. I've lived though the change to metric and my parents lived through the change to decimal currency from shillings etc just fine also so ultimately the US still uses Imperial because it works just fine and the hassle of changing isn't worth it.
- Only going to cost more down the line, sunk cost fallacy, etc...
  
  Not really, they can use them until they need to be replaced and then have the replacements have both.
  You'd have to have them in different cookies like Texas does with those bullshit fucking day/night speed limits
True. The U.S. is one of them.
In reality, while most countries don't use metric and imperial, they do use metric and some other local system of measurements. Many countries use both metric and their historically preferred system.
- .
- What non-metric system does Germany use? What non-metric system does France use? What non-metric system does Poland use?

US has imperial for everything but guns and drugs, there are countries that use a lot of both (like UK) but there are many countries that use no imperial

I live in a country that's gradually moved to metric over the last 30 years. The only thing we use imperial for now is height and pints in the pub. Older folks still use it for body weight.
Speed limits were less of an issue than you might think as they convert pretty closely - 30mph is very close to 50kph etc.
I love that a litre of water weighs a kilo and takes up 100 cubic centimetres.
- The only thing we use imperial for now is height and pints in the pub.
  There's a really good reason for this, the first being that there is no metric equivalent of a pint because if there was it would be 500ml and an imperial pint is 570ml, nobody wants less beer in their pint. Poor Americans have a 475ml pint.
  The height one (and any other remnants of imperial numeracy) is largely due to American cultural media exports and it's easier for non Americans to convert to American imperial units due to exposure to both, to engage in effective communication.
We use both for guns, caliber is imperial (.22, .45, etc).
We exclusively use metric for science
US has imperial for everything but guns and drugs
If we're talking legal drugs, my prescriptions all come in milligrams.
If we're talking illegal drugs, though fractions of ounces or pounds were more common, it wasn't unusual to come across someone selling stuff by the gram back in the day, and I can't imagine that's changed. The weed dude would sell any amount at $10/gram - and yes, I did see someone come with $3 once. 😂 I don't remember the coke dude's prices because that was much longer ago, but he was also totally fine with selling single grams.
Maybe my experience was different because I live in a college town, so the black market was supportive of the small purchases necessitated by student budgets.
everything but guns and drugs
Really shows their priorities
Drugs, guns, baking, construction, manufacturing... actually, the better way to put it would be "literally fucking everywhere but the road signs and speedometers."

The vast majority of the world does not use imperial units.

Oh really? So if I send blueprints to a steel fabricator in metric, they will not have a problem with that? Lol try again.

They'll only have a problem if you don't label your units or say somewhere what they are. And if you don't do that, that isn't an imperial vs metric problem, that's flat out bad engineering.
- You clearly have never worked with structural steel fabricators.
Um, they wouldn't have a problem with that. That's exactly what I used to do, fabricate steel parts for companies like Liebherr and Komatsu, who would send us blueprints in metric. My coworkers and I actually preferred it.
- I'm talking about architectural steel. Not mechanical engineering, structural. I-beams.

No. Also ur fat and eat hambugers

Now it's time for the school supplies joke