I don’t know how many times I read Jules Verne’s 20000 Leagues Under the Sea when I was growing up, but it was quite a few. Even then, long before the idea of learning Japanese had ever occurred to me, this passage describing the library aboard the Nautilus always made an impression:

Strange to say, all these books were irregularly arranged, in whatever language they were written; and this medley proved that the Captain of the Nautilus must have read indiscriminately the books which he took up by chance.

I think knowing Japanese so effortlessly that my library had no need for any particular “Japanese section” (or for that matter German, French, or Italian, since those are all waiting in the queue), would be an excellent goal marker to work toward.