This dates back to 1992, when Mattel put out Teen Talk Barbie, whose programmed phrases included “Math class is tough” and “Want to go shopping? Okay, meet me at the mall”. A lot of media attention was given to the negative response the gender stereotype the two phrases illustrated. Ben Zimmer detailed the development of this snowclone on Language Log in March 2006, noting that the Usenet group soc.mtss
made extensive use of it.
Variants of X (as of a Google search today) include i830, irony, dialogue, science, neuroscience, and data synchronization. I find it intriguing that all of these things really are hard in the right context. (Ask a writer whether dialogue is hard!) I know science can be hard to explain to people who don’t understand the scientific method. Many of these snowclones seem intended to open discussion on what actually makes X difficult, using the snowclone to signal that the user is not taking himself too seriously. I am not sure if this is necessarily the prevailing intention of modern users of the snowclone, but it is interesting to note.
So lots of things can fill the X slot; there isn’t a semantic limitation that I can see, other than possibly the aforementioned things-that-are-actually-difficult.
Another Language Log post by Ben Zimmer on this snowclone can be found here.