&gt; I prefer no spaces around em-dashes for the entirely subjective reason that I find it aesthetically pleasing. It boggles my mind that other people look at an elegant em-dash and think, &quot;Yes... with spaces... now it looks right.&quot;<p>I think it&#x27;s because with no spaces, an em-dash looks like it&#x27;s connecting two words into a single word.<p>Name another phrase-level punctuation mark (period, comma, semicolon, colon, quote, question mark, ellipses, parentheses) which isn&#x27;t connected to a space.  There&#x27;s a reason for that.<p>[Hyphens, apostrophes, slashes, etc. are word-level.]