Everyday, as an American

ISO8601 gang

Represeeeeent!
Some ISO8601 formats are good, but some are unreadable (like 20240607T054831Z for date and time).
- The ones without separators tend to be for server/client exchange though.
  
  I agree but they're hard to read at a glance when debugging and there's lots of them :)
  Having said that, a lot of client-server communications use Unix timestamps though, which are even harder to read at a glance.
  
  At least it’s human readable and not protobuf 😬 * though the transport channel doesn’t really matter it could be formatted this way anyhow.
- I mean I like this one without the separations

While we at that, lets switch to the international fixed calendar as well.

That one feels kinda meh to me. It solves a handful of non-issues with our current calendar (I don't care that the month starts on the same day, nor do I care that each day of the year is always the same day of the week). Each months having the same number of days is an improvement. It persists the problem that you still can't use months or years as a real mathematical unit of measure and extends it to weeks, which is the biggest annoyance with calendars, although it reduces how often that becomes significant. Adding two days that have neither a day of the week nor month would mean significant changes to every computer system that needs to deal with dates, and is just hateful.
The 1st of a month to the 1st of the next will always be one month, but it depends on the month and year how many days that is. So a month as a duration will span either 28 or 29 days. A week is now sometimes 8 days, and a year might still have 365 or 366 days, depending on the year.
How do you even write the date for the days that don't fit? Like, a form with a box for the date needs to be able to handle Y-M-D formatting but also Y-YearDay. Probably people would just say 06-29 and 12-29, or 07-00 and 01-00, although if year day is the last day of the year it kinda gets weird to say the last day of the year is the zeroth day of the first month of the next year.
There's just a lot of momentum behind a 12 month year with every day being part of a month and week. Like, more than 6000 years. You start to run into weird issues where people's religion dictates that every seventh days is special which we've currently built into our calendar.
Without actually solving significant issues, it's just change for changes sake.
- Well, this is shitpost. And I wasn't serious about this. I responded to someone that wants the whole world to switch to a global time, and since mankind existed we used some local time in our daily lives.
  Also UTC is not perfect because of leap seconds. Which means you cannot calculate with a simple formula how many seconds are between two time stamps, you need a leap seconds table for that. And leap seconds are only announced under 6 months into the future. So everything farther away, you cannot say how much time is between two stamps.
  So with UTC a minute can have more or less seconds that 60.
Since we're breaking everything, I want to use dozenal with the Pitman symbols and "deck/el" pronunciations.
Move New Years back to march 1st, then the Latin roots will be accurate again.
let's* switch
- lettuce* switch

YYYY.MM.DD and 24 hour for sure.

Everyone using UTC? Nah. Creates more problems than it solves (which are already solved, because you can just lookup what time it is elsewhere, and use calendars to automatically convert, etc.).

I for one do not want to do mental gymnastics /calculation just to know what solar time it is somewhere else. And if you just look up what solar time it is somewhere, we've already arrived back at what we're already doing.

Much easier just looking up what time (solar) time it is in a timezone. No need to re-learn what time means when you arrive somewhere on holiday, no need for movies to spell out exactly where they are in the world whenever they speak about time just so you know what it means. (Seriously, imagine how dumb it would be watching international films and they say: "meet you at 14 o'clock", and you have no idea what solar time that is, unless they literally tell you their timezone.)

Further, a lot more business than currently would have to start splitting their days not at 00:00 (I'm aware places like nightclubs do this already).

Getting rid of timezones makes no sense, and I do not understand why people on the internet keep suggesting it like it's a good idea.

I'm pretty sure they don't mean "give up on time zones" but "express your timezone in UTC". For example, central Europe is UTC+1. Makes almost no difference in everyday life, only when you tell someone in another zone your time. The idea is to have one common reference point and do the calculation immediately when someone gives you their UTC zone. For example, if you use pacific time and tell me that, it means nothing to me, but if you say "UTC-8" I know exactly what time it is for you.
- Oh right, yeah. We do this at my company which has operations world-wide. If we say timezone we say UTC±. Apologies for the misunderstanding

What about a format where we only have multiples of 10?

You mean base-10? My totally unrealistic pipe dream would be to have the world switch to base-12.
- I mean something like 1 day = 10 hours = 1 000 minutes = 100 000 seconds (currently 86 400 seconds so a second would only get slightly faster).
  
  https://en.m.wikipedia.org/wiki/Decimal_time
  This term is often used specifically to refer to the French Republican calendar time system used in France from 1794 to 1800, during the French Revolution, which divided the day into 10 decimal hours, each decimal hour into 100 decimal minutes and each decimal minute into 100 decimal seconds
  
  Oh, nice! It's funny how it's the same as the one I just made up which further proves that it simply makes sense.
  
  Yeah. I think if someone had a sensible method for how we could switch from one to the other with minimal impact, it might work.
  What would very difficult for me would be the recalibration of my internal clock. Knowing a second is slightly shorter, and a minute is longer, and an hour is much longer, would be hell for a while.
  Unfortunately I think something that's pretty hard coded into the society at this point is that a day should be able to divide by so we end up with the 8hr work, 8 hr rest, 8 hr sleep. I'd be interested in a 30hr day over a 10 hr day. But that one doesn't make much sense either since it misses the mark on bringing tim fully into the 10 base metric system, but still has all the same troubles you'd encounter for getting people to switch.

Seconded.

That's good for file/record sorting, so let's just use it for that

For day to day, DD.MM.YY is much more practical.

For day to day, DD.MM.YY is much more practical.
It's not though... It's ambiguous as to if the day or month is first. With the year first, there's no ambiguity.
If you want to use d-m-y then at least use month names (eg. 7-June-2024).
- It's ambiguous as to if the day or month is first.
  Not if everyone is using it, as they should.
  Besides, so is is yours. 2024.06.07 could be the 7th of June or (if you're an American and thus used to the months and days being in an illogical order) 6th of July.
  As for writing out the month names, that's no longer shorthand. That's just taking more time and space than necessary.
  
  Au contraire! With a three character month, period separation isn't needed, and the date is shorter. (Admittedly there's likely to be a language translation issue, depending on audience.)
Hard disagree.
Least specific -> most specific is generally better in spoken language as the first part spoken is the part the listener begins interpreting.
Like if I ask if you're free on "the 15th of March" vs "March 15", the first example is slightly jarring for your brain to interpret because at first it hears "15th" and starts processing all the 15ths it's aware of, then "March" to finally clarify which month the 15th is referencing.
The only thing practical about DD.MM.YY is that it is easier for the speaker because they can drop the implied information, or continue to add it as they develop the sentence.
"Are you free on the 15th" [oh shit, that's probably confusing, I meant a few months from now] "of July" [oh shit, I actually mean next summer not this one] "next year (or 2025)".
So the format is really a question of who is more important in spoken language: the speaker or the listener? And I firmly believe the listener is more important, because the entire point of communication is to take the idea you've formulated into your head, and accurately describe that idea in a way that recreates that same idea in the listener's head. Making it easier for the speaker to make a sentence is pointless if the sentence itself is confusing to the listener. That's literally a failure to communicate.
- You're confusing your own familiarity and experience with a general human rule.
  My mother tongue (Portuguese) has the same order when saying numbers as English (i.e. twenty seven) and indeed when I learned Dutch it was jarring that their number order is the reverse (i.e. seven and twenty) until I got used to it, by which point it stopped being jarring.
  The brain doesn't really care beyond "this is not how I'm used to parse numbers" and once you get used to do it that way, it works just as well.
  As for dates, people using year first is jarring to me, because I grew up hearing day first then month, then year. There is only one advantage for year first, which is very specifically when in text form, sorting by text dates written in year-month-day by alphabetical order will correctly sort by date, which is nice if you're a programmer (and the reason why when I need to have a date as part of a filename I'll user year first). Meanwhile the advantage of day first is that often you don't need to say the rest since if you don't it's implied as the present one (i.e. if I tell you now "let's have that meeting on the 10th" June and 2024 are implied) so you can convey the same infomation with less words (however in written form meant to preserve the date for future reference you have to write the whole thing anyway)
  Personally I recognize that it's mainly familiarity that makes me favour one format over the other and logically I don't think one way is overall better than the other one as the advantages of each are situational.
  
  Meanwhile the advantage of day first is that often you don't need to say the rest since if you don't it's implied as the present one (i.e. if I tell you now "let's have that meeting on the 10th" June and 2024 are implied) so you can convey the same infomation with less words (however in written form meant to preserve the date for future reference you have to write the whole thing anyway)
  That advantage is not exclusive to the date-first system. You can still leave out implied information with month-first as well.
  Personally I recognize that it's mainly familiarity that makes me favour one format over the other and logically I don't think one way is overall better than the other one as the advantages of each are situational.
  This is the biggest part of it. No one wants to change what they know. I'm from the US and moved to the UK, and interact with continental Europeans on a daily basis. I've seen and used both systems day to day. But when I approach this question, my answer isn't "this one is better because that's the one I like or I'm most comfortable with", my answer is "if no one knew any system right now, and we all had to choose between one of the two options, which one is the more sensible option?"
  dd-mm-yyyy has no benefit over yyyy-mm-dd, while yyyy-mm-dd does have benefits over dd-mm-yyyy. The choice is easy.
  
  The minimal or non-existent benefits for most people in most situation of yyyy-mm-dd (no, the brain doesn't need the highest dimensional scale value to come first: that's just your own habit because of how numbers are spoken in the English language and possibly because the kind of situation where you use dates involves many things which are further than a year forwards or backwards in time, which for most people is unusual) - people sorting dates by alphabetical order in computer systems (which is where yyyy-mm-yy is the only one that works well) is just the product of either programmer laziness or people misusing text fields for dates - so don't add to enough to justify the "jarring" for other people due to changing from the date format they're used to, not the mention the costs in anything from having to change existing computer systems to having to redesign and print new paper forms with fill-in data fields with a different order.
  In a similar logic, the benefits of dd-mm-yyyy are mainly the ease of shortenning it in spoken language (i.e. just the day, or just the day and month) and depend on knowing the month and year of when a shortenned date was used (which usually doesn't work well for anything but immediate transfer of information as the month and day would still need to be store somewhere if they're not coming from "present date") so they too do not justify the "jarring" for other people due to changing from the date format they're used to.
  Frankly even in an imaginary situation were we would be starting from scratch and had to pick one, I don't know which one would be better since they both have flawed advantages - year first only really being advantageous for allowing misusing of text data fields or programmer laziness in computer systems whilst day first only being advantageous in immediate transfer of date information where it gives the possibility of using a shortenned date, something which is but a tiny gain in terms of time or, if in a computers system or written form, storage space.
  It's really not a hill worth dying on and I only answered your point because you seemed to be confusing how comfortable it felt for you to use one or the other - a comfort which derives from familiarization - with there being some kind of general cognitive advantage for using any order (which, in my experience, there is not).
- if I ask if you're free on "the 15th of March" vs "March 15", the first example is slightly jarring for your brain to interpret
  Sounds like you're just used to it being said the opposite (read: wrong) way. If you told someone in my country March 15th, it would be just as jarring to the listener.
  at first it hears "15th" and starts processing all the 15ths it's aware of, then "March" to finally clarify which month the 15th is referencing.
  not in daily use. When you ask someone "what day is it today?", they usually have a handle on what month it is and just need the day. For making plans, it's only if you make them way in advance that you need the month first, which would be sorting and scheduling, not daily use.
  
  When you ask someone "what day is it today?", they usually have a handle on what month it is and just need the day.
  You're still allowed to exclude implied information, no matter which method of dating you want to go with. You can just say "the 15th".
  For making plans, it's only if you make them way in advance that you need the month first, which would be sorting and scheduling, not daily use.
  I can't speak for you, but for me I am making plans, sorting, and scheduling every single day.
  
  I can't speak for you, but for me I am making plans, sorting, and scheduling every single day
  Sounds exhausting tbh, I'm sorry..