[Dylan16807]

You might not be stopped from going <tag></tag> but you are stopped from going <tag /> 90% of the time, which is annoying.

[stan_rogers]

That space before the closing slash is actually not allowed in XML, but was required for browsers that couldn't interpret XHTML. XHTML was broken from the get-go; the only virtue it had was that it taught a generation of web developers to be consistent in their markup.

(By the way, since sibling nodes have no specified order in XML, there's no reason why one paragraph should have followed another on a web page consistently, and the <ol> was an oxymoron.)