Over here, we don't really have middle initials. Or if we have, I've never encountered it.
But I guess my middle initials would be A.M, which stand for Anna Margareta. A great-grandmother on my mom's side was named Anna, and I guess Margareta must have a similar backstory...
It's funny, though; My middle names were a hair away from getting me into trouble when I was going home from Los Angeles last fall. I have a long and unusual last name, so due to the order the names are placed on American boarding passes (Last name first), my first name had actually gotten cut out off my boarding pass. The lady who checked it glared super hard at me and asked me for the proof of purchase (Or whatever it is called), which I gave to her. She checked it, compared to my passport, glared at me again and said: "It says here that your name is Margaret".
She did double check, though, saw that she was wrong ("Oh wait, that is you...") and sent me on my way. I was super scared that I'd be brought in for something...Then again, I had my family with me, so nothing might've come of it after all...