I will start:
a) as.Date(“2022-Jul-01”, format =“%Y-%b-%d”) will or will not work depending on os language
b) how R handles diacritics and encoding differently on Linux and on windows
c) Rstudio :D
utf Support under windows (which is not r’s fault) which might/will be (is already?) fixed
the rate at which packages change, sometimes breaking stuff (renv to the rescue)
how my place does not invest in proper integration but uses various scripts stored on a network drive with absolutely no documentation