[loganmhb]

One of the nice things about the Clojure standard library is that most everyday functions actually do fit the first/last category (by design). Functions operating on sequences (map, filter, reduce, etc) take the sequence as the last argument and are suited for use with the ->> macro, while functions operating on data structures in a non-sequence context typically take the data structure first (assoc, conj, update) and are good for ->. So you get either:

    (->> (range 10)
         (map inc)
         (filter even?)
         (take 2)) ;=> '(2 4)

or

    (-> {:body {:some {:json :data}}}
        (assoc-in [:body :some :more-json] :more-data)
        (assoc :status 200)
        (update :body json/generate-string))
    ;;=> {:body "{\"some\":{\"json\":\"data\",\"more-json\":\"more-data\"}}", :status 200}
        

It doesn't work all the time, obviously, and it can be easy to get carried away with 15 threaded map/filter/reduce calls that should be factored into separate functions, but most of the time I find it to be a nice idiom that substantially improves readability.