This is the kind of thing which infuriates me the most about emacs. There are thousands of similar but not equivalent ways of doing the same thing, both StackOverflow and the emacs wiki contains some (but not all, and not the same, and usually not the right, and usually contradictory) ways of doing things. And it's impossible to figure out which way is the right one without asking around in IRC channels.

Why oh why couldn't they improve linenum-mode instead of introducing a new mode.