I misspoke in my last comment when I referred to space and time complexity. The usual problem in the field isn't figuring out the big O characteristics, it's un

I misspoke in my last comment when I referred to space and time complexity. The usual problem in the field isn't figuring out the big O characteristics, it's unpredictable performance due to evaluation of an expression building up a huge chain of thunks. Because of the inherently non-local logic of lazy evaluation (or, whatever evaluation strategy compatible with non-strict semantics that GHC actually chooses to use), it is not always easy to find which piece of code is introducing unwanted laziness. That said, it's the same fundamental non-locality that also makes it more difficult to figure out the big O complexity of an algorithm implemented in a non-strict language.