Sean Penn says he hadn’t felt joy making a movie in 15 years.

At the time, the actor couldn’t quite put his finger on why, but he at one point became so disillusioned that he resigned himself to the reality that his love for the craft may never return.

“I’d felt misery in making movies,” the two- time Oscar winner recalled during a recent interview. “At first you’re putting it off to, ‘Well, this script is a problem, and this director is a problem.’ But then I caught myself a few times working on great things with great people and just as miserable.”

That is until his neighbor, Dakota Johnson, knocked on his door with a script and an invitation to be her co-star. “No reservations at all. I felt like you would feel getting your first movie,” Penn recalled of his initial response to reading “Daddio,” now in theaters.

But the film that reenchanted Penn with the art of making movies is by no means a typical Hollywood flick. Instead, “Daddio” is an austere portrait of an ephemeral, serendipitous human connection that feels rare nowadays, if not nearly extinct.

Part of what Penn appreciated about the script was its characters’ unfiltered frankness, something he thinks is missing in a lot of contemporary art and broader societal conversations.

“I think we’re stripping whole generations of diversity of behavior and diversity of personality,” he said, conceding that he understands concerns about sensitivity, but only to a point. “Changing one’s vocabulary or altering it in certain circumstances becomes the full-time job and reflective thought is left behind.”

“Daddio” follows Girlie (Johnson), a woman who is returning to New York after a trip out of state. The film begins with her getting in a cab at JFK airport and ends with her getting dropped off at home. The 90 minutes in between are filled with ostensibly mundane but revealing conversations between Girlie and her cab driver, Clark (Penn).

“Daddio” is the feature debut of writer-director Christy Hall, who, perhaps unsurprisingly given that the film is driven by dialogue, has a background in theater. Hall began working on the script in 2014, inspired in part by her nostalgia for the reality series “Taxicab Confessions.”

Penn, like he does in many of his roles, brings a masculine energy that gives life to a brash and foul-mouthed cabbie, but one who ultimately proves to have a tenderness.

Similarly, Johnson’s Girlie is a savvy, successful software engineer who appears to have it all together, but whose relationship with her father — or lack thereof — ultimately leads her to seek that love elsewhere.

“This movie is about the human condition, that there’s two sides to all of us. We’re always contending with our greater angels and our darkest demons. And I’m interested in characters that are always contending with both, because that’s actually the truth,” Hall said.

“Daddio” will undoubtedly test some viewers’ attention spans, but others will find themselves drawn in by the candid and compelling conversation between these strangers about sex, father issues and being “the other woman.”

Johnson said she “attacked” the script for “Daddio” when she first read it because she loved it so much, and she spent years through her production company, TeaTime, working with Hall to get the film financed. After years in limbo, it was eventually picked up by Sony Pictures Classics.

Johnson hopes to savor the joy she feels coming off this film and to remember it the next time she’s fighting for a project.

“I think that humans are craving human connection,” she said. “Maybe it’s because of social media or what we have been sort of dealt in terms of entertainment in the last five, 10 years. … It doesn’t give us the content that I think we subconsciously crave.”