October 15th

Invasion of the Body Snatchers (1978) directed by Philip Kaufman

Ideological isolation: that's the fear I see in this version of the story. Early in the film, when Elizabeth explains to Matthew that her boyfriend Geoffrey doesn't seem the same to her, he tells her to see a psychiatrist. Matthew explains that the shrink

...would eliminate whether Geoffrey was having an affair, or had become gay. Whether he had a social disease, or had become a Republican. 

That last bit in there seems like a joke, but what if it's not? What if the population of the notoriously liberal San Francisco started to change into Republicans overnight? The unaffected natives would suddenly find their viewpoint increasingly in the minority. No longer would they be able to comfortably assume that most people they met shared their perspective. Before the discovery of Jack's duplicate body, Elizabeth is continually noticing people in the street sharing secret looks with each other, and when she follows Geoffrey he is having secret meetings. When they glance at her, it's with a dead stare the tells her she's an outsider. Few things could feel more alien than suddenly being excluded like this.

What if society moved onto a different way of thinking and left you behind? Would you pretend to go along with the flow to fit in, or would you steadfastly hold onto your beliefs? How long could you hold out if everyone else thought of things differently from you? We do have examples of this in the real world and they rarely turn out well. I'm thinking of a guy like the Unabomber, or even Elliot Rodger. Being unable to fit in can drive you nuts.