“[People] live with anger, hostility, problems, lack of money, lack of—you know, tremendous disappointments in their life. So what they need is a philosophy. What everybody needs is a way to say, Where and how can I love? Can I be in love so that I can live, so that I can live with some degree of peace. And so that’s why I have a need for the characters to really analyze love, discuss it, kill it, destroy it, hurt each other, do all that...the rest of the stuff doesn’t really interest me.”—John Cassavetes

John Cassavetes’ A Woman Under the Influence is about staying in love, and how difficult that is. With a running time of 155 minutes, the film is an ordeal and is about ordeals. The first shot finds men waist-deep in muddied water. They’re moving something large. No explanation is given for their labor; their faces are indistinct. They’re straining to move what looks like a massive corner piece of water pipe; they’re straining to move in the brown current of a stream wedged between two sloping hulks of soil. Everything is a struggle.

The characters come into relief from this backdrop of labor and anxiety: Peter Falk is Nick Longhetti, a construction foreman who cares for the men working under him. He’s the kind of guy you instinctively trust because his heart beats loudly and nakedly. His men applaud after he tells off the bosses during a tense phone call, yelling that they won’t work through the night, they’ve worked enough, and—listen—he has a date with his wife. Who? My wife, my wife, my wife, he shouts. He cares deeply, and this is one of the reasons why things won’t work out.

Gena Rowlands is Mabel Longhetti, and when we first see her she’s shouting, too. She’s frantic on her own front lawn, barely staying inside her shoes and pushing her unruly blonde hair around her head while overseeing the complex task of packing three young children into her mother’s car. The kids are spending the night with Grandma to facilitate what must be one of the most important dates in the history of this marriage. The atmosphere is cataclysmic, like everything is riding on the success of this date. Of course, it’ll fail.

A Woman Under the Influence, Cassavetes’s seventh film as a director, convulses with plans that always tailspin. He’s known as one of the key figures in the creation of American independent cinema as both a financial necessity and as an idiosyncratic style with its own tropes and motifs; and like so many of the greats, he was drawn to failure, and to documenting it with extreme care and detail. In A Woman Under the Influence, an impromptu lunch sours into crushing silence and embarrassment. A children’s party explodes into violence. Cassavetes prefers long takes and medium shots; he dilates moments to unbearable lengths to best capture the brutality of domestic spaces turned upside down. There are maybe a dozen scenes in this movie, and the majority work hard at shattering the safety and propriety of the traditional setting for ideal familial happiness and love. It makes you want to cry.

Rowlands is the center. This movie opened 40 years ago today (according to IMDb, anyway—the film's release was slow and methodical, with Cassavetes taking the print across the country, from city to city, like a play, because he couldn't acquire proper distribution) and her performance hasn’t aged a second. The story goes that Cassavetes, who was Rowlands’s husband from 1954 until the day he died, on February 3, 1989, wrote A Woman Under the Influence as a play after she told him she wanted to work on something about the struggles of contemporary women. So he wrote for her and when she read the finished piece, she told him it would be impossible to perform on the regular basis that theater requires. “I’d have to be hospitalized,” she said.

Financing the film version involved mortgaging their house, among other personal sacrifices, not limited to using friends and family as performers and asking those friends and family for money. Peter Falk was one such friend and long-time collaborator. Thanks to a TV show called Columbo, he added half a million to the kitty.

Maybe the genesis of the project isn’t terribly interesting, but it’s a welcome distraction after the viewing experience runs you over. Love is an insane condition, the film argues. Now, that’s on top of the actual mental health issues Mabel experiences. The film doesn’t provide long-winded back-story. Is there a history of mental illness in her family? Is this just the natural reaction to having a husband who’s away and three children that spend most of their hours in school, leaving you at home to watch the clock and chain smoke and drink and drink and drink. Could it be the only reasonable response to a home where privacy is only possible when it’s accompanied by terrible, chilly loneliness? The bathroom off of the Longhetti’s dining-room-cum-bedroom has two entrances, and one door bears a surreal sign that reads “PRIVATE.” It’s a cruel joke in a movie that works each of its select bits roughly. Comics kill a set, slay a crowd. This movie lets you in on a kind of pain that is performed so effectively, it actually hurts you.

Another joke: Mabel asks her father to stand up for her and he doesn’t get it. The camera doesn’t leave her face as you actually hear him push his chair back from the dinner table. He waits, then he sits back down. And then he stands up again when she repeats herself. He doesn’t fucking get it. But you do.

You also understand why her father acted the way he did. Mabel’s language is in constant flux. She’s always performing. Earlier in the film, she instructs her children and their friends to “die” for an adult chaperoning the party. They’re acting out a scene from Swan Lake at her urging, and it’s time for the death sequence. (This is another of the film’s jokes.) What she means from one moment to the next is subject to who Mabel is trying to please, and when she asks her father to stand up for her, he assumes another performance is afoot. He’s wrong. (The language in A Woman Under the Influence is so careful in its sloppiness and double meaning, it’s disrespectful to Cassavetes to describe the final product as loose or improvised, something that Falk and Rowlands have confirmed in interviews. In a supplement on the Criterion Collection’s release of the film, Falk says, “John has a reputation for being the father of improvisation...but John, as much as anything, was a writer...I often said, I bet I could make a lot of money betting you which scenes were improvised and which scenes weren't. Because you can't tell the difference. In that scene where [Rowlands] broke down, the idea that [she] would make all that up is just impossible.”)

So is it insane when I say that this is a hopeful movie? That it believes in work in that honest, heartbreaking American way, that it believes you work for those you love? Mabel and Nick labor for and love each other. They love each other even though they can’t talk about it in ways that the other understands. Their relationship labor is radically unproductive in this department. “JUST BE YOURSELF,” Nick cries to Mabel, like that means anything at all when your self is just the reflection in love of your partner.

It’s an impossible state of being that’s as common as rain. The proper depiction is anything but.

Ross Scarano is a deputy editor at Complex. He kept it together during the movie until they tucked the kids in for bed. He tweets here.