I did the same in elementary school. I started at the first shelf with the intention of reading every book in the non-fiction section as my plan to know everything I needed to know. I made it 4 or 5 shelves but then lost my determination when a librarian informed me that she was adding new books to the shelves I had finished. I then switched to a more directed reading agenda based on a plan.

I'm learning Dutch on Duolingo, and they recently updated the "Tree". Basically whenever they do that, you lose a lot of your "progress", and have to revisit (months of) previous sections that you'd already completed (because some new things are added to previous subjects). It sounds similar to what you described (very demotivating), and seems (from comments on the site) to especially affect people who are relatively newer to the site. I'm not sure yet, but I think there's a mismatch between gamification and motivation for actual learning.

I really like Kobo Abe too. I've read Woman in the Dunes, The Box Man, and The Ruined Map. Which others would you recommend?