My frustration came from the lack of a type system, and that there's no "myThing." (myThing-dot) to give you intellisense. Even many dynamic language editors have some variant of this now. So coding in Clojure involves too much looking stuff up and memorizing stuff, and is way slower than it should be in 2016.
In Scala, Java, C#, F#, C++, I can do `myArray.` and it shows all methods available to arrays. No Clojure editor has anything like this. JetBrains editors take it a step farther and even include "code template" options that apply. So typing "myArray." will also include options for "foreach, for, for-reverse" templates. This, in addition to automatically importing any required library for the method you select.
With Clojure, there's no "dot". You're stuck hunting through documentation, trying to figure out first which namespace your function belongs to, then requiring it, then figuring out which function you want. Cursive only helps out with that last step, and even then, it displays every function in the namespace, when generally you only want to see the functions that apply to your variable.
While I'm all about immutability and structured data types, I've grown slightly away from functional-first languages in general for that reason. Even in F#, you've got to do `myList |> List.map ... |> List.filter ...` etc, requiring more lookup than C#'s `myList.Select(...).Where(...)`. The "dot" is an underappreciated aspect of OOP.