She describes him as one of her "early-morning skinny latte set", so she felt comfortable giving him a knowing grimace. "They're an oddball lot - most of my generation would never vote for them,'' she said.
They had both been joshing good-humouredly over the Polish foreign affairs minister's aside that Ireland should ease up on its Brexit backstop fixation. The waitress from Warsaw is one of 120,000 Poles now living in Ireland. And here she was dissing her own government. She is a classic beneficiary of the EU-inspired 'Europe without borders' dream which has transformed the lives of her generation.
Ireland and Poland are separated by a distance of more than 2,000km. Yet there are remarkable cultural similarities forged by over two millennia of Roman Catholicism. Even in the international soccer arena it is no coincidence we have played Poland more often than any other country. Back in the day, when we found friendly matches hard to come by, it was the Poles who usually obliged.
So all things considered, we could be slightly miffed it is the only country to have broken ranks with us. As it happens, it doesn't much matter. The big guns - crucially the Germans and the French - remain onside. In any case, the Polish stance has more to do with its own internal politics; the current far-right government maintains a kind of love-hate relationship with Brussels.
Poland stays in the EU - just as it remains a member of Nato - because of the protection offered against an ever-present Russian threat. But there is a special irony the minister has such little sympathy with our border worries. Few countries in history have suffered as much as Poland in trying to protect its frontiers.
The country's relationship with the EU remains uneasy. There are fears traditional Polish beliefs and culture are under threat. Politicians charge Brussels mandarins with excessive interference on matters such as immigration and LGBT rights. For its part, the EU is concerned about Polish judicial independence.
Inevitably, there was gloating in some quarters following the foreign policy jibe. Some hoped it was a sign the dam would burst, and Ireland 'would be thrown under the EU bus'. Recent days have also seen increasing vitriol directed against those who, in whatever fashion, support the backstop. The most oft-used insinuation is that most are 'sneakin' regarders' harbouring deep and destructive anti-British feelings. Even more serious is the accusation they are part of some pan-nationalist ideology, determined to use Brexit as a battering ram for Irish unity. However, apart from Sinn Féin diehards, and a minority of extremists, there is no evidence this is the case.
Regardless of a certain needle Brexit has introduced into Irish-British discourse, a durable rancour between both countries will not last in the longer term. In the Republic of Ireland, views on Irish unity have evolved dramatically in recent years. The overwhelming majority do not obsess about the issue on any level, and with ever-increasing education levels, most Irish people embrace British culture with unprecedented ease and assurance.
But there is widespread concern a new North-south divide could return a segment of the Northern Ireland population to a kind of limbo, where old grievances once again simmer. It's a pity some DUP leading lights seem so unfeeling on this issue. Their language has been too harsh and unyielding.
Of course, if Britain crashes out without a deal there will be unparalleled challenges for the Government here. However, despite ongoing hysteria it is unlikely we will have a no-deal Brexit - unless it should happen by accident. A wide spectrum of British political life is determined this simply will not happen.
In the meantime, Leo Varadkar and Simon Coveney should hold firm, unless a better backstop offer comes along. Their stance is not anti-British or dismissive of Ulster unionism. Rather it's a legitimate attempt to preserve one of the central tenets which brought peace to this island. Traversing from Donegal to Derry, without fear or favour, is something priceless.
Coming from a place where her parents were long entrapped within the borders of communist Poland makes it an experience the coffee shop waitress fully understands.