A brief modern history of Greece: Greece was occupied by the Ottoman Empire for 500 years and were kindly given a loan by the British to set up their state and to try and militarily finish off the remnants of the Ottoman Empire (a dismal military failure) at the behest European players.
Then there was WWI where Greece was involved in various military conflicts in the Balkan region (against German allies) just to have a Bavarian king imposed on them at the end of WWI by the major European players.
Then we had WWII. A large portion of the Greek debt is also due to the damage inflicted during WWII by the Nazi occupation. The Nazi government of Germany forced the Greek goverment to loan them huge sums of money of which they neve paid back. Greece also received no reparations from Germany at the end of WWII (which all of the other major European players did) and was then forced to restructure under the Marshall Plan.
It then slipped into a civil war which lead to (a US backed) military dictatorship (anything to stop the USSR) during which Cyprus was invaded by Turkey which lead to military stockpiling by both sides (kindly supplied, brought from that is, the major European players and the US). Greece spends 4.3% of its GDP on military spending, that's the 2nd highest percentage in Europe! The only country with a higher percentage is the Republic of Macedonia, and everybody is trying to get Greece to go to war with them over the use of various ancient symbols!!!
Add to this: corruption, government incompetency, a large unproductive (well, non-profit producing) civil service, capital flight to the Bulgaria (where the wages are 1/3 and the country is run by the mafia after the collapse of the Stalinist regime) after the collapse of the Eastern Bloc, a non-functional tax collection system... the list goes on.
And one can get some sort of idea why Greece is in debt.
High social welfare? Bullshit! Greeks are lazy and don't work? Bullshit! Socialistic measures? Well yes and no. It was not so much the Socialistic measures but the fact that most of the money which was slated for investment was lost on government bribes and a lack of control mechanisms on how it was spent. Liberal sex culture??? WTF? How can this possibly lead to a debt crisis? Lazy youth culture? Well apart from the Nazi youth and Stalinist youth cultures I think you will find that kids everywhere in the world want to (and should) play. It's their prerogative.