The meme coming out of Europe, and from conservative America, is that Greece a) lied about their debt, b) foolishly borrowed more and lived the high life, and c) now simply don't want to pay it back.
There is a grain of truth to this, but only a grain. It's important to see both sides.

The Greek government did intentionally hide their debts levels, with the help of Goldman Sachs, before joining the Euro.
Speaking of that, Goldman Sachs may be sued for their deception.

So the Greek government did in fact lie to get into the Euro. You can understand why that might not sit well with Germany and the other European creditors.

The next point is that Greece borrowed money to live the high life.
This is where the criticism of Greece jumps the rails.
You see, one of the largest reasons that Greece got into this mess isn't from welfare giveaways. It's from military defense spending.

Still, despite Greece's staggering economic problems, the country has consistently maintained one of the highest defense expenditures as a percentage of GDP in all of Europe.
For 2015, NATO projects that Greece will spend 2.4% of its GDP on defense, which is actually a 0.1% increase in spending over 2014.

Why is that? Largely it's because Greece isn't exactly friendly with almost of all its neighbors. But there is also another reason.

The final reason Athens may have been reluctant to cut defense spending is political pressure from Germany and France, the Guardian notes. Berlin sent almost 15% of its arms exports to Greece in 2012, with France sending almost 10% in 2012.
According to the Stockholm International Peace Research Institute, Greece continued to buy large quantities of weaponry from the two countries between 2010 to 2014, some of the worst years of its economic depression. During this time, Athens bought $551 million worth of military equipment from Germany and $136 million of equipment from France.

Back in 2010, when Greece's economy was starting to meltdown, Germany was busy selling Greece two submarines, while France was looking to sell Greece six frigates and 15 search-and-rescue helicopters.
This is blatant hypocrisy.

What's more, it wasn't just excessive defense spending. There was extreme levels of corruption inside the Greek version of the Pentagon.

When Antonis Kantas, a deputy in the Defense Ministry here, spoke up against the purchase of expensive German-made tanks in 2001, a representative of the tank’s manufacturer stopped by his office to leave a satchel on his sofa. It contained 600,000 euros, about $814,000.
...
The €600,000, for instance, bought Mr. Kantas’s silence on the tanks, which were deemed of little value in any wars Greece might fight, according to Constantinos P. Fraggos, an expert on the Greek military who has written several books on the subject. Greece went ahead and bought 170 of the tanks for about $2.3 billion.
Adding to the absurdity of the purchase (almost all of it on credit), the ministry bought virtually no ammunition for them, Mr. Fraggos said. It also bought fighter planes without electronic guidance systems and paid more than $4 billion for troubled, noisy submarines that are not yet finished and sit today virtually abandoned in a shipyard outside Athens.

Sure, the Greek officials were corrupt. But who was paying them off? The same people who are judging them today!
Isn't there laws about nullifying contracts when bribery is involved?

There is more than a grain of truth that Greece's welfare state was far in excess of what it could afford...in 2009.
The austerity imposed since then is far in excess of anything else seen north of Africa.
Greece has cut their pension payments by an average of 40% in five years.

Because of those pension cuts, 45% of retirees in Greece live below the poverty line

Because of the economic Depression, pensions are the main source of income for 49% of Greek families

Because of all these cuts, 20%of Greeks 'no longer have enough money to cover daily food expenses'.

Greece now spends only 5% of GDP on public health, the least in Europe. 25% of Greeks no longer have health insurance.

HIV infections are up 200% and malaria has returned.

Suicides are up 45% and infant mortality is up 43%.

Hospital budgets have been slashed 50% and spending on mental health has been cut 55%.

The TB rate has doubled

And now we are looking at more and deeper cuts. It is estimated that the old austerity package will knock 1.51% off GDP this year and 2.87% next year. The new package will be even worse.

German and French military contractors, along with corrupt Greek military officials and politicians benefited from this massive borrowing, but the Greek people being asked to pay for it got none of the benefits.

Finally, there is the claim that Greece simply doesn't want to pay the money back.
As a new IMF report concludes, it's not a case of wanting. It's a case of ability.

The latest IMF study said Greek debt would now peak at close to 200 percent of economic output in the next two years, compared to a previously forecast high of 177 percent.
Even by 2022, the debt would stand at 170 percent of gross domestic product, compared to an estimate of 142 percent issued just two weeks ago.
Gross financing needs would rise to above the 15 percent of GDP threshold deemed safe and continue rising in the long term, the updated IMF study said.
Moreover, the latest projections "remain subject to considerable downside risk", meaning that euro zone countries might have to provide even more exceptional financing.
In the laconic technocratic language of IMF officialdom, the report noted that few countries had ever managed to sustain for several decades the primary budget surplus of 3.5 percent of GDP expected of Greece.

As Paul Krugman has pointed out time and time again, austerity crushes economic growth. Greece is already in an economic depression.

Many have pointed out that Germany's WWII debts were largely written off by the allies, one of which was Greece.
Yet the irony goes even deeper than that today.

they must simply hand over “valuable Greek assets of €50 billion” to be privatised – flogged off to decrease the debt. Who will do the privatising? Schäuble proposes that these Greek state assets – airports, electricity companies, whatever – should be surrendered to a body called the “Institution for Growth in Luxembourg”. And who is in charge of this institution, eh? Jawohl, meine Freunde! It turns out to be a front for the German KfW, the Kreditanstalt für Wiederaufbau, the state development bank that was set up, ironically, as part of the postwar Marshall plan to rescue the bombed-out German economy.

We've left economics behind long ago. This is all about politics. Germany wanted to send a message to the rest of Europe, and the comparison to how Europe approaches Ukraine displays this message in unmistakable fashion.

For international financial discipline, then, to prove that all debts must be paid? Hardly – consider that in March the IMF, with almost no fuss, announced a financial package for a European country that is far more corrupt, unstable and oligarchic than Greece.
Ukraine got €36.1 billion in assistance from the IMF, including write-offs of previous IMF loans worth between €13.5 billion and €18 billion. There is little chance of any of this money ever being paid back. And yet Angela Merkel and the other EU hardliners had no problem with any of this.
Why? It’s the politics stupid.

As the article articulates, there are 'those who are brought to heel and those who shout “Heel!”'