Yanis Varoufakis, Greece's finance minister, smiles during a panel discussion at the Brookings Institution on the sidelines of the International Monetary Fund (IMF) and World Bank Group Spring Meetings in Washington, D.C., U.S., on Thursday, April 16, 2015. International Monetary Fund Managing Director Christine Lagarde warned that she wouldn't let Greece skip a debt payment to the lender, shutting down a potential avenue to buy the Greek government some financial leeway. Photographer: Andrew Harrer/Bloomberg via Getty Images