both of my rare car sightings were when I worked at a gas station way back when I was still a teenager.
saw one of these:
not sure of the exact year, but it was definitely a Silver Cloud and was immaculate. very cool car to see up close.
also once had customer come in driving a canary yellow Cutlass convertible (around a 1970 or so, cant remember the year for certain). nothing particularly rare about that, except the it had right-hand steering. thats right, the steering wheel was on the right side of the car. was an overseas model that had been broght over by the owner (a serviceman) who couldnt bear to part with it when he returned stateside.