The sour tone at the end of the Salzburg summit could all just be part of the negotiations dance.
In an ambush that blindsided British officials, Donald Tusk, the European Council president, dismissed her Chequers proposals as unworkable after a private meeting of national leaders.
The Best for Britain group said their statements showed "there is still time for the United Kingdom to check with the people if Brexit is what they still want".
They've spent two days in Salzburg, Austria trying to do just that, but with no clear solution in sight, the sides have tried to ramp up pressure on each other.
He said: "It was a good and courageous step by the Prime Minister. If sentiment sours making a "no deal" scenario more likely, then we could see the pound tumble", said City Index analyst Kathleen Brooks.
Pro-Brexit members of May's Conservative Party also oppose her deal, saying it would keep Britain tethered to the bloc, with no say over its rules and unable to strike new trade deals around the world.
The caption appears to be a reminder of the European Union's stance on May "cherry-picking" elements of the EU's single market in her Chequers plan.
"Not least because it risks underlining the single market..."
"It must be clear that there are some issues where we are not ready to compromise, first off the four fundamental freedoms, the Single Market, this is why we remain sceptical of Chequers", Mr Tusk said.
Paul Whiteley, a professor of politics and government at the University of Essex, explains the latest on the unfolding Brexit process. We need to find a deal, a no-deal is a really bad solution. Neither side wants an arrangement that would require the rebuilding of border infrastructure, the removal of which was a key part of the Good Friday Agreement that brought peace to Northern Ireland after years of sectarian strife.
Asked about the rejection of Chequers, May said she had expected that "at various stages of these negotiations, tactics would be used".
While both Britain and the European Union agree that imposing a hard Irish border would threaten a very hard-won peace on the island, May insisted that there was no way she could allow anyone to "divide the United Kingdom into two customs territories".
The Chequers plan could not be regarded as a "take it or leave it" offer, Mr Macron said, adding that he hoped there would be "new British propositions" on the table by October.
"The Brexit teaches us something - and I completely respect British sovereignty when I say that - it showed that those who say that we can easily live without Europe, that everything is going to be alright, and that it's going to bring in a lot of money are liars", he said.
- Dutch Prime Minister Mark Rutte said his country is better prepared for a no-deal Brexit than Britain and an agreement is "not easy" because of Mrs May's red lines.
"Of course, we've heard those voices in Europe that talk about a second referendum -- actually, others have now started to recognise more that this is going to happen, we are going to leave the EU".
"We are today at the moment of truth", Macron warned.
It all suggests a fractious summit in Brussels next month.