[zmoazeni]

Just throwing my voice into the chorus, I know nothing about category theory either, and I don't think that hinders learning Haskell.

I do think there is a subset of Haskellers who use category theory to prove certain ideas and they are able to easily express that in code. However I haven't found it necessary to understand the theory behind why something is sound in order to practically use their work in my projects. That says more about Haskell's expressiveness than the target audience to me.

Setting aside years of imperative (and also OO) programming and learning a different approach to solving problems has been the biggest challenge for me, by far. That's why I agree wholeheartedly with https://news.ycombinator.com/item?id=7687200