It's sometimes difficult to know with the American version of Who Do You Think You Are?, where real emotions end and synthetic ones begin.
Remember, for instance, Sarah Jessica Parker's multiple "Wows", "Oohs" and "Aahs" during her recent journey into her family's past? It was like watching orgasm outtakes from Sex and the City 2.
There were moments when you felt poor SJP would melt into a puddle of tears if someone so much as told her that her great-great-grandfather's fluffy little puppy was run over by a wagon in the 1700s. And that was BEFORE she learned an ancestor of hers had narrowly escaped death during the Salem witch trials.
There was no such problem when Lisa Kudrow, aka kooky Phoebe from Friends and also an executive producer on this series, traced the history of her great- grandparents, East European Jews who, like millions of others, fell foul of the Nazis.
This was authentically moving television and easily the most compelling episode of WDYTYA? USA so far.
Kudrow learned fairly early on how her paternal great-grandmother, who lived in a small village near Minsk in Belarus, had died at the hands of Hitler's hordes.
She visited the site, now a memorial, where some 900 Jews -- men, women and children -- had been dragged from their homes, taken to the village square, stripped naked, machine-gunned three or four at a time, and then dumped into a frozen pit where ice for food storage was kept.
The grisly record books revealed that her great-grandmother had been shot, then burned. There was no overblown, SJP-style emoting from Kudrow. Just a few quiet, soft tears and a wordless soaking up of the horror of it all.
But the quest was really about finding out what happened to her father's distant cousin Yuri Barudin, who initially alerted the family to the fact that the Nazis had arrived in the village on a murderous rampage.
Kudrow's father, Lee -- who escaped the carnage as a little boy, grew up in a tough immigrant neighbourhood in New York and pulled himself up by his bootstraps to become a doctor -- recalled Yuri running into their house, telling them the news, patting him on the head and then departing, never to be seen again.
Lee had always been led to believe that Yuri had died during the Second World War, while serving aboard a ship. However, when Kudrow tracked down the ship's manifest, it revealed that someone by the name of Barudin had been discharged as late as 1950.
Archives in Poland revealed that this Barudin had married, settled down and had a son. Could it be the same man? As so often seems to be the case in these programmes, the answer was to be found in the simplest source imaginable: the phone book.
A nervous, emotional call by Kudrow established that this Barudin was indeed Yuri and that he was still alive -- although for whatever reason, he'd long since changed his first name to something else.
You have to concede that there's a certain amount of contrivance and artifice in Who Do You Think You Are?
Much of the research, you suspect, has already been done by experts before the camera starts rolling.
Yet the moment when Kudrow met the elderly Yuri, his son and his grandson at their home was a delightful one. There was unexpected humour too.
"Lisa Kudrow is in my home and not on my TV?" said Yuri's delighted son, obviously a Friends fan. "This is amazing!"
It transpired that during the war, Yuri had been taken by the Russians to Siberia, where he joined the Russian army and later somehow managed to "jump" to the Polish army.
The programme ended with Lee Kudrow taking a Skype video call from Yuri in Poland -- a genuinely happy, lump-in-the-throat ending to a fantastic story.
WHO DO YOU THINK YOU ARE? USA ***