I visited Germany first (Nordrhein Westfalen) and was almost fluent after a while. I was seventeen. Because I was not waking up before 8 AM, so the family that invited me thought I a was a kind of hippie. But they were although impressed by my ability to speak their German language. German people do think like soldiers and peasants that the world belongs to people who wake up early.
(It's a good thing for French people to visit Germany to understand Voltaire.)
Then I visited USA and it was a G-shock. Females rule on German males because they are soldiers (loving music). Females rule on US males too because they are gangsters (loving rockn'roll). This travel helped me for many reasons. I did not trust democracy a lot, because only hypocrits French artists or philosophers tell us that democracy is not a trick. And after my travel I could not believe in it at all, because money obviously rules USA (the money of Chinese workers), and nothing else.
It helped me to understand too that my Roman catholic religion was wrong. And I started to read and try to understand the Revelation Book that Roman catholic Church is trying to dig under its art and 'traditions' as the plot of Pharisian clerks and widows tried to kill Jesus-Christ... but failed in this satanic plot.