Indeed. But I am not sure if "crazy" is the right word. Perhaps a better one would be "dense". It is not unlike reading a mathematical proof - one paragraph might need an one semester course to be explained.

This is perfectly nice:

firstBatch = take 10 myDoubles

This is not that nice: sieve (p:ps) xs = h ++ sieve ps [x | x <- t, rem x p /=0] where (h,~(_:t)) = span(< p*p) xs

But that's because there's just too many things going on. A comparable Java code would likely span a page.

I guess, for a trained eye, it is way easier to understand what's going on given those two lines, then a full page program, which would likely hide bugs in side effects.