The one where I could use backticked reference in real code

I alway liked that in Haskell you can inflix a function with backticks like this:

take 5 [1..]

-- is the same as

5 `take` [1..]

You can do a similar thing in R. In R, when you surround for example an operator, like [], or +, you can use it like a normal function. This is because these operators are also function calls.
Until now I couldn’t really use this in real life code, but the other day I had to scrape wikipedia and it was pretty handy.

suppressPackageStartupMessages({
  library(tidyverse)
  library(rvest)
})

# Wiki page for European cities
cities_wiki <- "https://en.wikipedia.org/wiki/List_of_European_cities_by_population_within_city_limits"

# rvest function to read html
eu_cities <- read_html(cities_wiki)

# take the table on the site and extract the cities
cities <- eu_cities %>%
  html_nodes("table") %>%
  html_table() %>%
  `[[`(2) %>% 
  `$`(City)

head(cities)

## [1] "Istanbul[a]"      "Moscow[b]"        "London"          
## [4] "Saint Petersburg" "Berlin"           "Madrid"