I have just one question: what’s in it for them?

The EU’s only good feature is freedom of movement of people. How must the negotiations sound to Bulgarians now?

“You can join the EU!”
“Oh great, what are the benefits?”
“Freedom of movement of people; unfortunately there’s loads of expensive regulation and bureaucracy but you get freedom of movement.”
“Excellent, when can we join?” replied the Bulgar.
“1st January 2006 — oh, but you won’t be able to move around freely within the EU.”
“So, could you list those benefits again please?” (warily)

etc.