Stranger On A Train -- Odd Sensations -

The scent of a stranger’s perfume, a specific brand of coffee, or the metallic tang of the brakes can trigger "Proustian moments"—flashback memories that feel out of place in a commute.

Psychologists have long noted a phenomenon where people confess their deepest secrets to a seatmate they will never see again. Because there is no shared social circle and a clear "end time" to the encounter, the stranger becomes a secular confessor. You might find yourself explaining your divorce or a childhood fear to a man eating a ham sandwich, feeling a bizarre, fleeting soul-bond that vanishes the moment the doors hiss open. Stranger on a Train -- Odd Sensations

The muffled roar of the tunnel creates a sensory deprivation chamber. When the train emerges into the light, the sudden "pop" of sound and color can feel like waking up from a dream. The scent of a stranger’s perfume, a specific