Not enough lol <| sep |> This . I like this answer . Can I use this whenever people complain again ? <| sep |> One concept that thousands of bureaucrats will be thinking about is Economic friction . Frictional costs are the costs that arise because the real world is messy . Regulations , imperfect information , imperfect rationality , menu costs , transaction costs , timeeffort costs , imperfectly mobile labor , and many other things can contribute to frictional costs . The EU is a giant project in reducing frictional costs . If you have one currency you reduce all the costs and the time and effort aka the friction from having to change currency so much . If you have a common travel area you reduce passport friction . If you have a righttowork concept , you increase labor mobility and decrease friction even more . If you have a single set of unified regulation , the friction is lower and it ' s much easier for companies to follow the unified guidelines instead of following 20 sets of separate rules . Here ' s a fun example of how this might work in practice US eggs would be illegal to sell in the UK , and UK eggs would be illegal to sell in the US . This is because they use two different methods of cleaning the egg . Both the US and UK systems of egg cleaning produce perfectly safe eggs , but the regulations are contradictory and you can ' t fulfill one while also fulfilling the other . So no trade in eggs occurs between the two countries , even though one country certainly enjoys comparative advantage and trade would likely benefit both parties . Multiply that small egg example over the millions of different complex scenarios that occur in a fragmented continent like Europe , and you can see why reducing frictional costs is a big deal . Now the UK is leaving the EU , and they ' re probably anxious not to introduce a boatload of frictions into their economy when they do . This is why the negotiations will be so intense there ' s a tug of war between ' national sovereignty ' and ' keep frictional costs low by doing all the same stuff the EU does '.