zlacker

In LaTeX (and probably smartypants which is another of those bare pre-unicode ASCII to fancy text converters that can get stacked into markdown--but I can't remember if dash handling specifically is in there), "--" is en-dash and "---" is em-dash. The single "-" gives a hypen which is handled differently than an en-dash in typesetting.

So... that's just to say that people who are exposed to the sorts of can't-unsee-it-now typesetting OCD that LaTeX and various popular extension packages within that ecosystem exposes can learn to write write "--" as en-dash.

It's sort of like being unable to return to the blissful state of not being hyperaware that Ariel and Helvetica are different.