What on earth is going on in the films of John Cassavetes? Any movie lover is bound to confront that question, perhaps under a cloud of misconceptions and secondhand impressions. Maybe you heard that Cassavetes, a critical figure in American independent film, had ushered in a new era of realism in movies. Maybe you saw “Shadows,” which inaugurated the actor’s directorial career in the late 1950s, and believed its closing title card: “The film you have just seen was an improvisation.” (It wasn’t, at least in any meaningful sense; the “Shadows” most of us know revised an earlier feature.)

And watching the fits of pure impulse that animate “Husbands” (1970) — in which three mourning friends suddenly jet off to London, among other surprises — or the childlike mannerisms of the characters that Gena Rowlands, Cassavetes’s wife, sometimes played, it is tempting to ask: Would anyone actually behave this way?

But Cassavetes’s films offer shades of humor, joy, terror and sadness that have no analogues elsewhere in cinema. Crucial to understanding them is the realization that “raw” is not the same as “recognizable,” and that if his films deserve the loaded label of realism, it is only in a sense that he creates characters whose psychologies are too personal to classify. That is even the subject of his wonderful “Opening Night” (1977): Rowlands plays an unraveling actress unable to perform until she has synced with her role’s idiosyncrasies.