One aspect of debt - if repayment is in question

Some time ago I heard a joke that tells the story of how hard it is to deal in a certain part of the world ( not Greece I might add ). It goes like this:

A banker, whose bank has just made a large loan to a foreign company gets a phone call from an officer of that company. It goes like this:

Client - "Hello I'm phoning to reduce the interest rate on the large loan issued yesterday"

Banker - "But yesterday we signed a contract and agreed the rate !"

Client - "But yesterday I don't have your money ...."

The point is clear and is perhaps what's making the next step in the Greek debt tragedy so difficult.