For some reason, probably laziness, I never bother learning one of the classic *nix text editors, vi or emacs. Normally, I simply use nano / pico since there is no need to learn them first, and I usually avoid programming from the command-line.
However for some reason MS Services for Unix's (SFU) version of crontab seems to ignore the EDITOR environment variable (I actually compiled nano from source) and always uses vi as the editor. This forced me to learn vi.
I found a nice little tutorial on using vi which probably a good thing to read if you are using any form of unix.