I dropped Spanish which was the only language offered during my high school years. I regret it, and now I'm embarrassed to start learning as a uni-aged guy. I want to learn Mandarin because then I would know English and Mandarin which would cover like 50% of the populations speaking abilities.
Basically I just feel like a dumb American and being a Marxist I need to know another language.
In that vein, there's always the old FSI courses. Designed to get US diplomats fluent as fast as possible. People say good things about them. It's all audio, though, I think. So it depends what you like. Not sure if there's a Japanese course.
To be fair, listening is probably the most important part of learning a foreign language (for most learners) and perhaps requires the most time to develop. In every day life, listening and thus conversation/exchanges requires instant comprehension, and that's also a huge part of how we form social connections/associations with each other. With reading you can generally take your time to digest things.
Strongly agree. The accent has to be just right for me, though. Otherwise I can't put my ears through it. That's why I like listening-reading. I go by content and accent, and get 7–35+ hours with a voice that I can listen endlessly to.