The tonal shift is one of the cheapest weapons in a filmmaker's arsenal. Wielded properly, it can jolt spectators out of complacency and keep them on their toes for the remainder of the story. It can also cast new light on what's come before, as in Wolf, prompting spectators to reconsider their first impressions and approach the material from multiple angles. I'm more interested in this type of shift (though, as a fan of Takashi Miike's Audition, I'm a sucker for the other kind)—in the best instances, it can clue you into an entire layer of the movie you hadn't noticed.
Since I wrote about it three months ago, I've thought a good deal about Sebastian Silva's pseudohorror movie Magic Magic, whose final moment is almost as jarring as that of Wolf of Wall Street. (Spoilers ahead.) After growing steadily more nightmarish, the film ends abruptly, before we can find out whether Juno Temple's character is dead or merely in a catatonic state. The soundtrack has built to a din of music, panicked shouts, and troubling offscreen noises, but the final line stands out. It's the Temple character's cousin (Emily Browning) begging, "Please come back to us!"
That line is the film's most naked expression of emotion. It's especially jarring—after an hour and a half of passive-aggressive, innuendo, and other coded forms of behavior—to see one person reach out so directly to another. In this sudden turn, Silva reveals that the horror he'd been trying to convey through all sorts of mysterious effects (including allusions to the supernatural) is in fact rather mundane. The movie had been about the fear of living in isolation from other people—which, to a humanist like Silva, might be the greatest fear of all. In hindsight, Magic Magic seems a far more compassionate film than it does on first impression.