Joining the Euro is optional, several countries have not. Joining Schengen is optional, several countries have not. I'll grant you the laws part but if you read

Joining the Euro is optional, several countries have not. Joining Schengen is optional, several countries have not. I'll grant you the laws part but if you read them you might find you like them. Edit: You perhaps meant free-movement of people from other EU states, which is true, but generally considered a mutual-benefit.