One way I find traditional Lisp style more painful for functional code than Ruby is that fully functional-style Lisp pushes me to read and write code the opposite way from how I think about it. In the author's example:

    orders
      .select { |o| o.placed_at > 1.week.ago }
      .group_by(&:customer_id)
      .transform_values { |group| group.sum(&:total) }

the equivalent Lisp code would either be written in imperative style as multiple statements that each write to a temporary variable or (let) binding, or would look like this:

    (reduce #'+
      (map (lambda (o) (getf o 'total))
        ; this group_by replacement function
        ; might be written as hash-table code
        (my-group-by 'customer-id
          (remove-if-not
            (lambda (o)
              (>
                (getf o 'placed-at)
                (- (my-now) (* 60 60 24 7))))
            orders))))

where I now have to read from bottom to top to understand the order of operations on the `orders` record set, even though when I wrote the code earlier, I "logically" thought from first operation to last when deciding which high-level operations to use in which order.

Other imperative languages that support functional code either make you do things imperatively to get the "logical" ordering of functional operations like I feel Lisp pushes you to do, or they do something like Ruby where things can be chained left to right in a "single" statement even for operations that were not thought of ahead of time by the creators of opaque data structures you later need to operate on. (Everything is a user-extensible object like Ruby, unified function call syntax in D, extension methods in C#, or pipelines of structured objects in PowerShell.)