My experience with clojure/haskell tells me that order of arguments of common functions feels horribly wrong sometimes.

I've noticed that, too. One of the answers/comments for this question suggests that (for Haskell, at least) the order of arguments is chosen to be in decreasing probability of partial application. Maybe that accounts for the odd feel.

I guess there are no guarantees. Which ones are you thinking of in Haskell? There it seems to matter more.

I always seem to struggle with array/list indexing functions.

Like these?

  > let lst = [1,2,3]
  > lst!!0
  1
  > lst!!1
  2
  > let arr = listArray (0,2) [1,2,3]
  > arr!0
  1
  > arr!2
  2

I don't see how it would be particularly helpful to have the arguments to the indexing functions the other way around, but in case you really like the index coming before the list/array, you can always do

  > (!0) arr
  1
  > (!!1) lst
  2

I was going to say that learning clojure, I get confused because some of the functions are backwards from haskell. So, I think maybe there's just not consensus about what's the best order.

I had exactly the same experience when doing a project in Racket after using Haskell for a while. For what it's worth, I like the Haskell ordering more in most cases.