It wasn't an issue, but a minor annoyance to fix it every time I traveled, so that it matched my travel documents.
Until a couple of years ago, when I was traveling back from Germany and the flight crew thought it would be nice to surprise me with a bottle of champagne at midnight on my "birthday".
They were so proud of doing this over the top "random kindness" (it was pretty thoughtful), and couldn't figure out why I was confused and annoyed. I still feel bad for not acting more excited or grateful...
Yes, I know, historically it was.
I don't know why, but I can easily map 1-6 to Jan-Jun. And I can easily map 9-12 with Sep-Dec. But July and August always trip me up.
Jan01, Fev02, Mar03, Apr04, May05, Jun06, Jul07, Ago08, Sep09, Oct10, Nov11, Dec12