Fun anecdote: In Sweden it's not uncommon for people to have their middle name first in the passport. For example a person named Gustav Sven Andersson might actually have Sven as his "first name". This of course causes problems in the US which assumes everyone's first name is the one that comes first in their passport. I have several friends who have just given up and go by a different name in the US (ESTA, immigration, plane tickets etc).