This Motley Fool series examines things that just aren't right in the world of finance and investing. Here's what's got us riled up this week. If something's bugging you, too -- and we suspect it is -- go ahead and unload in the comments section below.

Today's subject: When a government is beset by financial crisis, common sense dictates that it should pare back spending. Alas, to quote Voltaire, common sense is not so common. Thousands of Greeks are now protesting, even rioting, over the austerity measures their government has imposed to battle its disastrous debt. The Greeks' indignation seems shameful, if not downright bizarre.

Unfortunately, Greece's problems are only the tip of the iceberg for our global economic worries. Too many countries continue to carry unsustainable levels of debt.

Why you should be indignant: I'm not surprised that Germany and several other EU countries have balked at helping out their misbegotten Mediterranean neighbor. Greece not only spent more than it had, but also fudged its numbers to hide that fiscally irresponsible behavior. (As if it needed more bad publicity at the moment, Goldman Sachs (NYSE: GS) allegedly helped Greece conceal its debts.)

Last year, Greece's budget deficit reached 12.7% of its GDP, while its national debt as a percentage of GDP hit roughly 125%. My Foolish colleague Jordan DiPietro recently pointed out that Greece blatantly disobeyed EU deficit and debt rules to get into this mess, which has now become a huge risk to the Eurozone.

The IMF has agreed to help (with austerity strings attached), but its contribution seems like a short-term Band-Aid at best; Greece's costs will still outpace the fund's infusion. The easiest ways to right Greece's finances include tough methods that are unpopular with its citizens: VAT taxes, pension cuts, higher retirement ages, and firing unproductive government workers. And that means the possibility of continued, and perhaps escalating, social unrest.

Of course, Greece's woes have also fueled fears that its debt will spread throughout the Eurozone, triggering similar fiscal difficulties for Spain, Portugal, and Italy. Across the board, sovereign debt could become our next big crisis to worry about.

What now: I wouldn't touch Greek stocks like DryShips (Nasdaq: DRYS) or National Bank of Greece (NYSE: NBG) with a 10-foot pole right now. And while I'm wary of investing in Greek companies, I believe Fools should also exercise greater caution when investing here in the U.S.

Greece's current mess is a near-perfect parable about the fate of any culture that relies on debt and fiscal recklessness to achieve the illusion of prosperity -- only to clamor for bailouts and safety nets when that mirage eventually vanishes. How is the massive U.S. debt any less serious a problem than Greece's?

The U.S. Government Accountability Office said earlier this year that in 2009, the U.S. budget deficit reached 9.9% of GDP, the largest such proportion since 1945. The total U.S. public debt currently represents 62% of GDP, and it's estimated to hit 100% of GDP by the end of 2011.Without policy changes, such debt growth is unsustainable.

In addition, the GAO revealed models of a not-so-distant future where, without major (and politically difficult) policy shifts, most federal revenue will go toward entitlement programs like Medicare, Medicaid, and Social Security, with the rest servicing interest on the burgeoning public debt. In other words, over the next several decades, there will be little money left over for defense, education, welfare, highway and mass transit investment, and many other priorities. On a purely realistic economic basis, something's got to give.

As concerned as I am, I think it would be a mistake to give up on stocks. I still consider strong, cash-rich companies with wide competitive moats the safest investments. I'd choose cash-rich companies like Apple (Nasdaq: AAPL) or Google (Nasdaq: GOOG), both of which enjoy solid consumer loyalty and a strong history of forward-looking innovation. I'd avoid struggling, overly indebted companies like Blockbuster (NYSE: BBI) or Borders (NYSE: BGP), which exemplify the long-term dangers of irresponsible debts.  

However much much happy talk we hear about U.S. economic recovery and stock market rallies, investors shouldn't underestimate the risks inherent in our gigantic national debt. Like Greece, our government's been spending money it doesn't have to make up for shortfalls from organic economic growth, all to create an illusion of "business as usual." Sorry, Keynesians, but Greece and the Eurozone clearly show that long-term deficit spending is a lousy game plan for governments.

Shame on Greece, and on anyone who riots against reality. If we can't realize the importance of fiscal responsibility within our own borders, the current Greek tragedy may not be as far away as it seems.

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Alyce Lomax does not own shares of any of the companies mentioned. The Fool has a disclosure policy.