It's not hard, though. Anybody can go online and search for an email validating regex, but as some have pointed out, many are too strict and don't allow for, say, tagged email addresses (email+tag@example.com). There's email validation, and there's overkill. That's what I was trying to get at.
The difficulty of writing regexes for email validation wasn't the main point - the main point was that emails don't follow spec so any regex based on that is inherently wrong. However, it seems like saying "most email validation regexes are broken" is equivalent to saying "email validation regex is hard"
