One really underappreciated aspect of R is that it's a lisp at heart. This enables the user (and enterprising package writer) to build really clean abstractions for the task at hand.

The tidyverse suite of Hadley Wickham is a great example of this, notably with the pipe operator %>% (similar to |> in F#) which is not part of the base language and yet could be very easily implemented. Julia's macros probably enables the same type of implementation, but I don't see how one would achieve it as easily in Python for example. Non-standard evaluation is another example of R's lispiness in action [0].

Also, consider how easy it is to walk R's S-exp. Expressions in R can only be one of four things: an atomic value, a name, a call or a pairlist. Wickham's Advanced R has a great intro on this [1].

I believe Wickham's amazing work with tidyverse (which really changes the way you code in R) is just the beginning of a rediscovery of R's inner lisp power, a kind of "R: the good parts" moment.

[0] http://adv-r.had.co.nz/Computing-on-the-language.html

[1] http://adv-r.had.co.nz/Expressions.html