The EU wasn't super fond of the UK to begin with, then they go and make things worse for every EU country by doing some stupid and unnecessary political move, add the increase in racism and xenophobia, and the decades of UK media spinning the EU as the bad guys, the very real benefit to Germany and France of seeing the "end of London", all this while leaving the EU is actually supported by a majority (or close to it at this moment) of the UK population, and has political benefits for people on both sides, given all this and more, it just shouldn't be that complicated for the EU to nudge the UK into pulling article 50, considering the massive difference in political and economical power between the 2.