It must have been the sisters that got to me: with their instinctive protectiveness towards a brother. Faces etched with pain and voices buckling under the weight of sudden and almost unbearable loss are commonplace here in Northern Ireland, so it couldn't only have been that.
Neither is courageous dignity on the part of bereaved relatives particularly novel. No, it must have been the sisterly love that breached my defences. Perhaps recalling my own two sisters' fiercely protective attitude to each of their crowd of eight younger brothers.
Whatever the spark, the pleas of the McCartney sisters for proper justice following the brutal murder of their brother, Robert (33), outside a Belfast bar three weeks ago, touched a chord with me, and with many others as well.
Decent, ordinary people, determined to hold fast to their decency, they were at pains to make clear it is only proper justice they are interested in, not the "summary" kind.
Normally, in this part of the world, after making the right noises and quietly thanking God it wasn't us or ours, we cross to the other side of the street and move quickly on our way, emotions barely ruffled. But the McCartney sisters jolted us out of our protective lethargy and dragged back to the surface again a basic humanity that has been too long submerged beneath tragedy heaped upon tragedy.
That this casual butchery happened in Belfast is, on its own, of little significance; it could just as easily have happened in virtually any town or village in Northern Ireland. And, outside the political ramifications, neither is it of particular import that it was off-duty republican paramilitaries who were responsible: it could have been paramilitaries of any stripe.
Locality determines which paramilitary group's members are beating you to death or to a pulp, not any recognisable difference in standards of morality or behaviour.
It's estimated that at least 70 people were present in Magennis's bar when Robert McCartney and his friend, Brendan Devine, were attacked. At time of writing, not one witness has come forward to the police to make a formal statement identifying the killers.
Afterwards, as the two men lay bleeding (and, in Robert's case, dying) outside on the street, before being noticed by a passing police patrol, no one bothered to call an ambulance.
So, can we take it from that, that everyone who witnessed the vicious attack and murder, was either supportive of the attackers or simply didn't care? No, even in Northern Ireland basic humanity has not yet been submerged deep enough to be able to ignore such butchery at close quarters.
Instead, it clearly illustrates the extent to which paramilitaries wield almost total power and control over those they live and socialise amongst.
A control based not on support, loyalty or admiration, but on an acquiescence bred from abject and well-founded fear. Where there is power without any measure of accountability, and particularly where it rests in the hands of those least qualified to hold it, it is wielded endlessly and, progressively, with more and more brutality.
In Northern Ireland, as the untouchables luxuriate in their invincibility, the local communities become ever quieter. How else to explain the silence of 70-odd witnesses to the brutal murder of Robert McCartney? How else to explain, in recent times, the communal silence that followed a senior paramilitary attempting to rape an underage girl; or another using a steam iron to burn the breasts of a young woman; or a "volunteer" throwing his girlfriend from a balcony while on holiday in Spain? All the above, and God knows what else, involved people living within a mile of Magennis's bar.
The same things are happening in communities all over the North, and, as in Belfast, people are too terrified to speak out.
In a display of helpless naivety, some of Robert McCartney's neighbours, in strictly off-the-record interviews of course, were quoted as saying: "If only the leadership knew what was happening here."
It was chillingly reminiscent of the plaintive cries of Soviet and German citizens, who just couldn't bring themselves to believe that Uncle Joe or their beloved Führer had any idea what was happening in their localities.
But, like Stalin and Hitler, the leaderships in the North know only too well what happens in the areas under their control.
They publicly distance themselves from the actions of their "volunteers" only when it becomes impossible for them not to do so - which isn't very often.
Pious-sounding statements from leaders are invariably driven by opportunism or damage limitation: not any sense of what is right or wrong. When you are in control, you decide what is right and what is wrong.
Robert McCartney's sisters have broken from the crowd to demand justice for their brother, and I hope they are successful. I hope, too, that more people follow their example and the walls of silence begin to crumble.
For while the silence remains, the untouchables continue to wallow in their invincibility, and we pay a terrible price.