Towards the end of Noah Baumbach’s latest film, While We’re Young, protagonist Josh (Ben Stiller) laments the feeling of being a “child imitating an adult.” It’s a familiar, facile observation. It’s the kind of thing that people say when their life is absent real concerns – about money, illness or the like – and they’re content to focus on #firstworldproblems. That’s the position the characters of both While We’re Young and Sarah Polley’s Take This Waltz find themselves in; yet the films’ distinct approaches to middle-class ennui pay very different dividends.

It’s not entirely clear how any of the people in these films sustain themselves financially. While We’re Young centres on the lives of Josh, a failed documentarian who hasn’t released a film in a decade, his wife, Cornelia (Naomi Watts), who’s apparently a producer. They live in a modern New York apartment despite no apparent income and we’re left to assume that Cornelia’s father – a hugely successful documentarian himself – is supporting their lifestyle. We’ll make the same assumptions about the young hipster couple they befriend, Jamie (Adam Driver) and Darby (Amanda Seyfried), who similarly have no apparent source of income despite their expansive, elaborately adorned loft.

I should clarify that I am resolutely anti-nitpicking. Films have no obligation, necessarily, to exist in a world approaching ‘reality.’ But the goals of a film determine whether or not these details matter. While We’re Young seems to have three goals; firstly, to operate as a loose comedy of manners about the insecurities of ageing (as suggested by its springy trailer). It succeeds along these lines for the first half hour or so, eliciting the occasional chuckle, before Baumbach tips his hand to its second goal: a kind of commentary on How We Live Now. This is where the film is least successful. Prepare yourself for wry montages of young people using old things and old people using new things (Jamie and Darby watch The Howling on videotape while Josh uses his Apple TV to browse Netflix!), the contrast between a ‘baby dance’ class and a hip-hop class or, worst of all, a scene of a toddler confidently using an iPhone that’s sure to have your parents clucking disapprovingly.

This second goal is doomed from the outset, because Baumbach doesn’t display sufficient cultural understanding to provide any meaningful commentary. Partly the problem is the overarching sense of privileged unreality. Equally, Jamie and Darby are broad caricatures – a 45 year old’s idea of what 25 year old hipsters are like nowadays (which makes sense given, y’know, Baumbach is 45, though films like Greenberg and particularly Frances Ha didn’t have this problem). Fine for an exaggerated comedy; not so much if you’re trying to make a meaningful statement about society.

About midway through the film we shift gears again, with Jamie transforming into a manipulative villain in his questionably ethical quest to make a “Facebook documentary.” Around this point While We’re Young turns into a pseudo-thriller impelled by questions of authenticity – what is “true” and what is “authentic” and why should we care? Perhaps you could make an argument that this ties into the unreality of the characters’ existence, but there’s no substantial link to my eyes. The biggest problem here is the film simply stops being entertaining, steamrolling the charisma of its performers with a sluggish narrative that erases the film’s already scant charms. There are still pleasures here, but it’s hard not to draw parallels between Josh’s documentary – overlong, unfocused – and the final product.

Take This Waltz is subject to many of the same complaints about authenticity. When I tweeted that I was watching the film, I received an even mix of fans expressing their appreciation for the film and detractors sneering at its implausibly comfortable protagonists. On the surface, those complaints aren’t invalid. Margot (Michelle Williams) is married to Lou (Seth Rogen), and they live in a nice suburban house despite working as a freelance writer and cookbook writer respectively. Even if we assume that these two are successful enough writers to fund their lifestyle, it’s hard to accept that their neighbour Daniel (Luke Kirby) can afford a roomy house over the road by working as a full-time rickshaw driver (he’s an artist, too, but he doesn’t sell his work – just as Darby makes ice cream in While We’re Young with no concrete plans to turn a profit).

Here’s the thing, though: in Take This Waltz, it doesn’t matter. Polley isn’t attempting to portray any larger truths about society, but rather to invest in the emotional experience of Margot. After sharing a plane ride with Daniel, she falls for him and spends the remainder of the film navigating her own feelings for her husband – comfortable, affectionate – and the intense, romantic feelings she develops for her neighbour. It’s entirely apropos, then, that Daniel is a kind of a fantasy figure (it’s no accident, I suspect, that she first meets him at a medieval fair – an apotheosis of idealised fantasy). He’s the boy next door. He’s handsome. He’s sexy. He has nothing but time for her. He’s an escape from the strictures of adult life.

That last part’s important. Josh’s idle observation in While We’re Young about being a child in an adult’s body is a cliché, sure, but a cliché that’s integral to Take This Waltz. Margot is, fundamentally, a child. She finds joy in play: rolling around with Lou on the kitchen floor or cackling as she pees in the pool at an aqua-aerobics class. The strictures of adulthood – of everyday domesticity – sit uncomfortably with her. She finds it hard to relate to her sister’s (Sarah Silverman’s) struggles with alcoholism. She wants romance, she wants dancing, she wants the life promised to her by the books and movies that she grew up with.

Polley sympathises with Margot’s desires – to a degree. The impossibility of this fantasy is emphasised in a pair of beautiful, mirrored scenes, scored to “Video Killed the Radio Star.” The first scene observes Margot and Daniel on an amusement park ride, and channels the complexity and musicality of infatuation effortlessly. It’s joyful then tender then sad then regretful, and all of these things at once. The final scene – of Margot imagining herself alone on that same ride, to the same song – is a potent portrayal of the incompatibility of fantasy and reality, a nuanced portrait of the challenges of adult life.

It’s scenes like this that, in my book, confirm Take This Waltz as a masterpiece. It’s not a perfect film – Rogen’s performance isn’t bad, but feels ill-suited to the film, while a recurring chicken metaphor is a touch overcooked. But it is a heartfelt, affecting film, one deeply invested in the interiority of its protagonist while acknowledging the impracticality of her dreams. It’s just as much about #firstworldproblems as While We’re Young, but unlike Baumbach’s film, Take This Waltz feels truthful.

While We’re Young Rating:Take This Waltz Rating: