[wodenokoto]

Looking at teaching materials, indexing in R hardly gets a mention. Student are told they get get the first element by a[1] and the twelfths element by a[12], and if you want 4th, 5th and 6th, you just ask for that range, a[4:6]

For python teaching this is almost a whole chapter, with people sharing cheat sheets and building graphics to show how slicing works what not. You don't see these things in R teaching materials.

I'm sure that for the implementation of algorithms, things might be easier with zero indexing, but for a user asking for element 4,5 and 6, 1-indexing is much, much easier on the user.