"Are you fundamentally unsound?"

This is the sort of question teenagers ask to sound worldly and wise, to imply a profound knowledge of human constitution. It confers authority with melodramatic flair, a trusted strategy among the newly self-aware. But this question sits at the heart of Manchester by the Sea, and when it is asked by 16-year-old Patrick (Lucas Hedges) to his uncle, Lee (Casey Affleck), after Patrick’s father, Joe (Kyle Chandler), dies of cardiac arrest, you realize there may be truth to it. It is asked in the heat of the moment—an exclamation rather than a probe—but it sticks.

The question could also be asked of the protagonists in director and writer Kenneth Lonergan’s previous two films, You Can Count on Me and Margaret, each of whom experiences a trauma that won’t leave. In the former, a brother and sister grow up in the wake of their parents’ premature deaths. In the latter, a teenager reckons with colossal guilt at an age when one struggles to understand her most basic feelings.

Trauma is a catalyzing force in Lonergan’s films, and Manchester by the Sea is driven by a pair: Joe’s death, and a fatal mistake by Lee that tears his family apart and consumes him, creating fault lines that tremble when exposed to pressure. After his brother’s death, Lee returns to Manchester by the Sea, the site of his family’s dissolution, a bitter and broken man who must determine how much he is willing to sacrifice for his nephew’s sake, how much of himself he can give. The question remains: Is he fundamentally unsound? At first, Lee seems like an anti-social crank, but as we learn of his past, the film locks into place and becomes a meditation on moving forward.

Lonergan has a soft spot for misfits, but the way he expresses that affection is neither romantic nor analytical. Rather, it is sensitive, but not in the way the word typically connotes. Lonergan’s sensitivity is directed toward the fundamental frustration of human interaction: We want desperately to understand each other, but we’re blocked from that understanding by our limited perspectives. We want to know what other people mean and feel, and we want other people to know the same of us. But we can’t achieve it, so we struggle for the right words and worry about what friends and strangers think of us.

Many scenes from Margaret render this tension vividly, including one in which the teenaged Lisa (Anna Paquin) is confronted by the friend, Emily, of a bus accident victim whose death Lisa partially caused. (To atone for her sins, Lisa pursues a wrongful death lawsuit with Emily and attempts to have the driver fired.) Upon probing Emily with too much force one afternoon, Emily snaps, “This is not an opera! We are not all supporting characters in the fascinating story of your life!” Lisa realizes her mistake and stumbles to explain herself, but the words come out wrong: hurried and frantic and desperate. Her best intentions dig a larger hole, and the scene ends with a divide placed between Lisa and Emily, two characters with common goals who split over semantics. It does not lead to an epiphany, as it might in most films, but rather illustrates the forces that keep us isolated.

A similar dynamic unfolds between Lee and Patrick after Joe’s death. They don’t change. They don’t become more insightful or compassionate. They make jokes at each other’s expense and don’t apologize. They often fail at empathy, even when they’re trying their hardest at it. When Patrick suffers an unexpected nervous breakdown, Lee, rather than soothe Patrick, attempts to contain him. His support is a blunt instrument when the situation requires delicacy. You see Lee grasp for the correct response, but it isn’t in him. His intentions can’t override his makeup.

Lonergan is at his best when he puts conflicting impulses in conversation with each other and his characters appear to be improvising, trying to make someone else understand what they’re feeling. He creates an energy and urgency; his words don’t come loaded with the cleverness and precise meanings favored by most Hollywood screenwriters. There is a searching quality in these moments, when you forget about the realities of narrative construction and believe you are watching people think in real time.

We see this when Patrick reunites with his estranged mother, Elise (Gretchen Mol), and her fiancée, Jeffrey (Matthew Broderick). Jeffrey is a devout Christian and Elise, a recovering alcoholic, finds comfort in the culture of religious doctrine. Patrick is abrasive and aggressive, but wants badly to reconnect with his mother, and each side strains to feign comfort in the other’s presence.

The scene is miscommunication in its purest form—a manner of failed expression rather than misaligned incentives. Jeffrey makes a light-hearted joke toward Patrick and takes Patrick’s meekly sarcastic response as a sign of obliviousness toward the joke. When Elise tells Patrick he doesn’t need to act so formally, Patrick insists he isn’t, but betrays discomfort in his answer. Here, the best intentions are spoiled by a fear of honesty, even when it would lead to the desired outcome. There is a thickness in the air that won’t clear.

This thickness is not a matter of visual style—as it would be in a David Fincher or Todd Haynes film—so much as acting, the kind of thing that comes from extended and deliberate rehearsal. Lonergan began his career as a playwright, and you can see in his films the theater’s reverence for words and inflections and gestures. You can see it in Manchester by the Sea’s “Oscar moment,” the scene which will surely run during the ceremony when Affleck and Michelle Williams, who plays Lee’s ex-wife, Randi, are recognized as nominees.

The scene is a chance encounter between Lee and Randi, who have not spoken much in the years since their divorce. Though the film makes clear that Lee could be a selfish and inattentive husband, Randi feels guilty about the things she said to him leading to their separation. Now, unexpectedly, she has the chance to say what she’s rehearsed in her head many times since.

And she speaks in the way you do when you’re given the chance to explain your guilt—nervously, tentatively. The scene hinges on a simple question, a variation on which we ask every day without much thought. She circles the question at first, fills the space around it and, finally— “Could we ever have lunch?” She glances up at Lee and the look says everything. In her eyes you see the years spent moving from anger to acceptance to guilt, her feelings for Lee that were forgotten, the fear that he might never forgive her. It is a sublime moment of acting, and Affleck nearly matches it. Lee is a stoic, but you see the feelings he’s shut off and locked away beating at their cages. For a few seconds, he looks vulnerable.

The film is less dynamic when it gives in to gloom. There is a sense of convenience—of course it is set during winter in the Northeast, of course the protagonist is emotionally distant—that creeps in sometimes and threatens to build tired formulas around it. But Affleck and Williams and Hedges never let it take that dive. There is always a spark in them—a twitch, a glance, a pair of eyes haunted by the past and scared of the future.