Greeks got used to living more-or-less as well as northern Europeans. They did this without earning enough income to afford their lifestyle.
Now the party is over. It's time for them to sober up, to deal with the consequences of living beyond their means. An "economic hangover" is no fun and they'd rather riot than face the music.
Michael Gerson, who writes for The Washington Post, has a good column on the economic problems of Europe and the halting efforts being taken to solve them. He is less than optimistic.