It's jarring when a film uses these devices when presenting actors who aren't stars, like some of the women who play Burt Lancaster's neighbors in The Swimmer or the people Joaquin Phoenix meets at the department store in The Master. Something in the back of your mind tells you these people should factor prominently in the narrative, even when nothing about the storytelling supports this suspicion. A similar effect is created when a film employs a performer wildly against type but in a small part that doesn't really weigh on the rest of the film. The Swimmer achieves this with Joan Rivers's cameo; so did Todd Solondz, in Happiness, in his casting of Marla Maples.
Among American directors, no one pulled off this trick better than Stanley Kubrick. In 2001 through Eyes Wide Shut, Kubrick consistently implies that we ought to recognize the people onscreen even when we have no idea who they are—an anxiety familiar from bad dreams. The Swimmer also conveys this nightmare anxiety, not only in its presentation of actors, but through the many elisions of Eleanor Perry's screenplay. Lancaster clearly has a history with every person he meets on his long "swim" home, though some of these relationships are only hinted at. I can see why the great actor considered his performance in The Swimmer his favorite—so much of the other characters' weight comes from how Lancaster regards them. In a sense, he is as much the film's director as Frank Perry or Sydney Pollack; his repressed, yet unwavering remorse reflects back on all the other characterizations.