Thanks for clarifying that. What I am trying to say with those two sentences is pretty unclear as worded. I'm trying to convey that the kind of Haskell you writ

Thanks for clarifying that. What I am trying to say with those two sentences is pretty unclear as worded. I'm trying to convey that the kind of Haskell you write as a beginner tends to perform well despite being wasteful. As you get better, you worry more about the waste and use more sophisticated stuff that's less wasteful. It obviously performs better, which isn't really what comes across. But it is usually a little more complex. The penalty is really slight for things like strict folds, strictness annotations and using better libraries like ByteString, but I'm sure you'll agree that it has a much more substantial effect on the look and feel of the code when you get to things like unboxing, using "raw" iteratees, and so forth.