Years of uncertainty and economic pain spent keeping Greece in the euro zone boils down in June to a handful of make-or-break debt repayments, while a raft of key data in the next few days will point to the progress of the global economy. The threat posed to the wider world by an eventual Greek exit from the euro may have diminished over the last few years, but last week the United States warned of an “accident” for the world economy if Greece and its creditors miss deadlines this coming month to avert a debt default.