My take – the exit from Euro is inevitable and unprecedented.

The good – Greece will have fiscal and monetary autonomy (no longer capped fiscal requirement by EU and can print their currency, Drachma). Greece can thus adopt expansionary fiscal and monetary policies more effectively to stimulate their AD instead of the proposed austerity measures by IMF and EU.

The bad & ugly – no longer have anymore access to creditors – IMF & EU. No one is going to lend money to some rogue whom have refused to make payment they have owed. Greece is on its own, a very painful restart for its economy. They have lost their last ounce of credibility.

https://www.quora.com/In-laymans-terms-what-is-the-Greek-debt-crisis/answer/Evan-Colvin