Thinking forward, I'd favor the EU's constitution (or whatever enshrines Article 50 and friends) being tweaked to require not merely a request for it to be triggered, but a requirement for a popular vote with some kind of supermajority involved, so nobody has to experience the ridiculous spectacle of 52-48 being hailed as some kind of mandate. If any country wishes to shoot itself in the head, there needs to be a genuine shift in public sentiment. Something at least 60-40, if not a US-style ⅔ majority.