I have an intense visceral hatred of the d/m/y date format. The country I live in uses it by convention, so that creates two problems. First, I have to put up with everybody else using it (not much I can do about that). Second, my computer is always displaying dates in that format, and I should be able to do something about that. I have patched and recompiled glibc for my locale, and that got rid of much of the problem, but KDE is stubbornly continuing to display dates in d/m/y format. The system settings app (personalizations / regional settings / formats) allows me to select the format from other countries, but that changes the language of days and months, so that is not really a solution.

I realize that KDE might inherit this behavior from QT (I have no idea), but even if so I am wondering if someone here knows a way to always get yyyy-mm-dd for the short date. Thank you in advance.

Digital clock example: viewtopic.php?f=17&t=134970&p=361132#p361132

Bump!
I'm also interested in this.
I share your vsiceral hatred of d/m/y, m/d/y and other backwards formats.
Only workaround I found is to change the Time locale (System Settings / Personalization / Regional Settings / Formats) to one that uses acceptable formats, e.g. Canada - Canadien English (en_CA) which writes 2016-07-29 9:41 PM
I'd much rather have the 24hr format but this is the most acceptable one I found.
New Zealand english doesn't get the long date format properly...
This should be customizable in details by the user instead of only allow to choose between preformated formats. It's a pity when KDE doesn't even give control to the user for something when even Windows does.