Impact of Greece is Inflated

Gross Domestic Product (GDP) of Greece is only 2% of the US GDP. Why does such an economically small country have enough impact on the US as to drive our stock markets down? Because, like so many things, the country is heavily leveraged, owing much to other countries. It should have no real impact, and yet it does. Governments must learn to exist within the means of their citizens and the citizens themselves must learn to be productive and not dependent.