When you're making a documentary series, your primary consideration is the talent. You can do all kinds of crazy stuff to make some interesting sausage out of whatever your ostensible subject is but without good talent you can do nothing.
In the first episode of the second season of the documentary series The Big Ward, which airs this Thursday, the first person we meet after charismatic, attractive, Lance O'Sullivan-esque surgeon and star Richard Babor is truculent, 200kg-plus, 20-year-old Jackson.
We stare for a long time at an almost cruelly intimate shot of Jackson sitting alone on a chair next to a vending machine in the antiseptic corridor of the Manukau Superclinic, where he is awaiting an important appointment with Babor regarding possible weight loss surgery.
Jackson shifts awkwardly in the chair, and appears to groan and possibly to sleep, behind his dark glasses and between his white earbuds. It's revealed via voiceover that he's hungover.
After a wait every bit as painful for us as for him, we follow him down the hall, listening to a disembodied interviewer ask him questions he clearly doesn't want to answer.
Every fibre in our remote-holding hands wants to switch the awkwardness off, to make the tension disappear, but we cannot. It is finely tuned high-wire television: anything could happen at any minute. We follow Jackson home, where we find out he has spent time in juvenile detention and was prepared to go to prison for offences he won't reveal.
The tension is finally released when we leave him behind to take up with Melissa, who is smiling and spinning her trolley in Pak'n Save, where she seems to be buying an outrageously large amount of bread-based items, particularly hot dog buns.
But within seconds, Melissa's sunny disposition, happy determination to ignore nutritional best practice, and high-quality improvised lines mark her out as not just A-grade talent but the perfect counterpoint to Jackson's quiet prickliness.
When she demonstrates for us, using a funnel, how her previous gastric band surgery has made it impossible for her to process certain foods, and we then wait outside the toilet door while she vomits back up a hot dog, it feels both imperative and impossible to look away.
But at that point we leave her story behind and cut to Josephine, who has been turned down for weight loss surgery five times already.
Josephine is instantly likeable, always smiling when she's not crying, holding hands with her mum in the waiting room at the Superclinic. She's compliant, hopeful, desperate.
She quickly finds a place in our hearts; she's the one we're really rooting for.
Will Josephine have lost enough weight to be considered for surgery?
We wait and hope as she's ushered in, the climax of the episode.
Within its opening half hour, The Big Ward's quality casting has made us feel fear, frustration, anger, sympathy, pity and joy.
The question of whether each of them will lose enough weight to get the surgery they need and of whether that surgery will make any difference to their lives is only part of what makes this good TV.
The journey is the thing. Results may vary.
The Big Ward TVNZ 2 Thursday, February 15, 8pm