Date and time formats -- (Rant)

Why is it that in this age of computers people still insist on such varied date and time formats?

It seems the best format should be YYYY-MM-DD for a date. The beauty is that it is unambiguous, and it sorts well. The year is the most significant part for crying out loud, so it should go first. Just like a number, right?

Dashes should be used because they go fine in file names. Most operating systems don't allow a '/' in a filename so the '-' makes the most sense here.

One of my pet peves is when people name files with a date stamp that places the day, or month before the year. It just doesn't make any sense.