I knew a vim-evangelist developer once who added bindings to his .vimrc file so that, if you pressed an arrow key in insert mode, it would insert the appropriate arrow symbol. I think this was meant to train the user _not_ to use the arrow keys to navigate around, but rather to switch to normal mode and use hjkl or other movement commands.

While I don't approve of this on a practical level, I have to admit that I find the logic of the joke hilarious. You were in insert mode, and you pressed the arrow key, so it ... inserted an arrow.