Having been an early supporter of the euro, I now consider my engagement to be the biggest professional mistake I have ever made. Here are the reasons:
First, politicians broke all their promises made in the Maastricht agreement. Not only was Greece let into the EU for purely political reasons, the Maastricht Treaty was broken more than 60 times. Mandatory punitive charges provided for such cases were never applied. To top it all, in May 2010 the 'no-bail-out' clause, the firewall between the German taxpayer and politicians in other countries, was broken down in the wake of the first Greek rescue package.