I've always been surprised that Pi Day is primarily evangelized by so many math / science / CS folks, when I would think it would be precisely these folks who hate the MM/DD/YYYY format. ISO format soothes my soul like a warm slice of apple pie with ice cream.

Pi Day is the same in Drunk Endian (US) and Big Endian (ISO Standard) formats (March 14th). It's different in Little Endian (Traditional European) format.

Yeah this thought mainly occurred to me when a big hubbub was made about 3.1415 day (3/14/15, or MM/DD/YYYY).

And, in the ISO format, when omitting the year, it's still 3-14.

I have been dating all official documents in ISO-8601 format and never had an issue with that in over 15 years. This includes bank forms, checks, contracts, and many other informal docs. Same for when my birthdate is requested of me. Even if the form has specific spaces for MM/DD/YYYY, I just write over it with the pen.

I assume you have the luxury of an unambiguous birthday (eg. 01-13). I imagine if I wrote 11-12 on a form without regard to what the specific spaces say, it would be regularly misinterpreted in the US.

No, both day and month are ≤ 12. Yet it seems to be OK.

Not if you include the year.

I once found myself confused as to how to date a US patent application, I was happy though to find that it was August 8th at the time.