This is what I found hard about Haskell. It's so tempting to DRY to such a phenomenal degree, but then the slightest requirement change somewhere in the middle

This is what I found hard about Haskell. It's so tempting to DRY to such a phenomenal degree, but then the slightest requirement change somewhere in the middle breaks some abstraction and bubbles all the way out. It's almost like how a zip encoding of two files that differ by one byte could be completely different.