It's also the most relevant information first. I don't care about what day it is if I don't know what month it's in. If it's an unambiguous context they can just be omitted.

Not only that. Processing logs with DD/MM/YYYY in many systems will result in octal base error because of the leading 0 in dates such as 07 08 09, and don't let me talk about how some languages read the back slash / pukes in shell

Easily proved to be the best: in every time travel story, the time traveler asks for the date. The unsuspecting drone always responds with DD or MM-DD, and the protagonist has to shout at them “NO! WHAT YEAR IS IT?”

Always start with YYYY.

I rest my case.

Gotta have that good sorting

Anything else is madness. It’s demonstrably the only logical answer.

DD is day in year, I think dd is what you mean. Also, YYYY is week year, so better to use yyyy.

yyyy-MM-dd

YMD is primarily used in:

China, Japan, South Korea, North Korea, Taiwan, Hungary, Mongolia, Lithuania, Bhutan, Sweden

That is one weird country group.

W E A R E I N E V I T A B L E

Either is preferable to the abomination in the meme.

It's entirely depend on the time frame range of your data. If it's wide it rapidly becomes useful to see the year first. In general I like to put 'larger' group variables in tables from left to right, helps in a similar way.

Pure beauty.

Yep; William Shatner.