> I might not find your examples compelling, because they require 2 passes over the data.

Are these the examples?

>> For example, if you want to fold over a partial data structure, you can use `filter` to select only the elements you want, and then fold over that subset. Or, if you want to exit early from a map, you can use `takeWhile` and only map over what's left.

These are done in a single pass. And if they weren't, I'd stop using them.