Japanese is a hard, hard language for Europeans to learn. Sure, the pronunciation is dead simple since once you get Romaji everything is pronounced as it is written. But the nuances of culture, in/out-group, cohai/sempai relationships, formality, and of course the kanji is so different than what we are used to.
I loved learning the language when I lived there in my early 20s since it taught me to contort my brain in ways that I didn’t know possible. But, now that I’m older, I don’t think I’d be able to do the same thing again (actually quite sad since I’ve forgotten about 95% of the language by now).